Unit Testing in a Nutshell - DroidKaigi 2018

Unit Testing in a Nutshell - DroidKaigi 2018
This is a reference material for this session
https://droidkaigi.jp/2018/timetable?session=16942
Hands-On
https://github.com/srym/DroidKaigi2018UnitTestHandOn

Transcript

1. Unit Testing in a Nutshell Fumihiko Shiroyama DroidKaigi 2018
2. Who is this guy? • Senior Android Developer @nikkei • Executive Beer Drinker • Chief Baby Sitter at home • Unit Test Enthusiast
3. Agenda today • Why you should care about Unit Testing • JUnit4 and basic assertions • Mock and spy with Mockito • Robolectric for framework's code • Unit Testing SQLite • Unit Testing asynchronous code • Best practices and tips
4. Why you should care about Unit Testing?
5. What if you DON'T?
6. public class LoginActivity extends AppCompatActivity implements LoaderCallbacks<Cursor> { private static final int REQUEST_READ_CONTACTS = 0; private static final String[] DUMMY_CREDENTIALS = new String[]{ "foo@example.com:hello", "bar@example.com:world" }; private UserLoginTask mAuthTask = null; private AutoCompleteTextView mEmailView; private EditText mPasswordView; private View mProgressView; private View mLoginFormView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_login); mEmailView = (AutoCompleteTextView) findViewById(R.id.email); populateAutoComplete(); mPasswordView = (EditText) findViewById(R.id.password); mPasswordView.setOnEditorActionListener(new TextView.OnEditorActionListener() { @Override public boolean onEditorAction(TextView textView, int id, KeyEvent keyEvent) { if (id == EditorInfo.IME_ACTION_DONE || id == EditorInfo.IME_NULL) { attemptLogin(); return true; } return false; } }); Button mEmailSignInButton = (Button) findViewById(R.id.email_sign_in_button); mEmailSignInButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View view) { attemptLogin(); } }); mLoginFormView = findViewById(R.id.login_form); mProgressView = findViewById(R.id.login_progress); } private void populateAutoComplete() { if (!mayRequestContacts()) { return; } getLoaderManager().initLoader(0, null, this); } private boolean mayRequestContacts() { if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) { return true; } if (checkSelfPermission(READ_CONTACTS) == PackageManager.PERMISSION_GRANTED) { return true; } if (shouldShowRequestPermissionRationale(READ_CONTACTS)) { Snackbar.make(mEmailView, R.string.permission_rationale, Snackbar.LENGTH_INDEFINITE) .setAction(android.R.string.ok, new View.OnClickListener() { @Override @TargetApi(Build.VERSION_CODES.M) public void onClick(View v) { requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS); } }); } else { requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS); } return false; } @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { if (requestCode == REQUEST_READ_CONTACTS) { if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { populateAutoComplete(); } } } private void attemptLogin() { if (mAuthTask != null) { return; } mEmailView.setError(null); mPasswordView.setError(null); String email = mEmailView.getText().toString(); String password = mPasswordView.getText().toString(); boolean cancel = false; View focusView = null; if (!TextUtils.isEmpty(password) && !isPasswordValid(password)) { mPasswordView.setError(getString(R.string.error_invalid_password)); focusView = mPasswordView; cancel = true; } if (TextUtils.isEmpty(email)) { mEmailView.setError(getString(R.string.error_field_required)); focusView = mEmailView; cancel = true; } else if (!isEmailValid(email)) { mEmailView.setError(getString(R.string.error_invalid_email)); focusView = mEmailView; cancel = true; } if (cancel) { focusView.requestFocus(); } else { showProgress(true); mAuthTask = new UserLoginTask(email, password); mAuthTask.execute((Void) null); } }
7. public class LoginActivity extends AppCompatActivity implements LoaderCallbacks<Cursor> { private static final int REQUEST_READ_CONTACTS = 0; private static final String[] DUMMY_CREDENTIALS = new String[]{ "foo@example.com:hello", "bar@example.com:world" }; private UserLoginTask mAuthTask = null; private AutoCompleteTextView mEmailView; private EditText mPasswordView; private View mProgressView; private View mLoginFormView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_login); mEmailView = (AutoCompleteTextView) findViewById(R.id.email); populateAutoComplete(); mPasswordView = (EditText) findViewById(R.id.password); mPasswordView.setOnEditorActionListener(new TextView.OnEditorActionListener() { @Override public boolean onEditorAction(TextView textView, int id, KeyEvent keyEvent) { if (id == EditorInfo.IME_ACTION_DONE || id == EditorInfo.IME_NULL) { attemptLogin(); return true; } return false; } }); Button mEmailSignInButton = (Button) findViewById(R.id.email_sign_in_button); mEmailSignInButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View view) { attemptLogin(); } }); mLoginFormView = findViewById(R.id.login_form); mProgressView = findViewById(R.id.login_progress); } private void populateAutoComplete() { if (!mayRequestContacts()) { return; } getLoaderManager().initLoader(0, null, this); } private boolean mayRequestContacts() { if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) { return true; } if (checkSelfPermission(READ_CONTACTS) == PackageManager.PERMISSION_GRANTED) { return true; } if (shouldShowRequestPermissionRationale(READ_CONTACTS)) { Snackbar.make(mEmailView, R.string.permission_rationale, Snackbar.LENGTH_INDEFINITE) .setAction(android.R.string.ok, new View.OnClickListener() { @Override @TargetApi(Build.VERSION_CODES.M) public void onClick(View v) { requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS); } }); } else { requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS); } return false; } @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { if (requestCode == REQUEST_READ_CONTACTS) { if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { populateAutoComplete(); } } } private void attemptLogin() { if (mAuthTask != null) { return; } mEmailView.setError(null); mPasswordView.setError(null); String email = mEmailView.getText().toString(); String password = mPasswordView.getText().toString(); boolean cancel = false; View focusView = null; if (!TextUtils.isEmpty(password) && !isPasswordValid(password)) { mPasswordView.setError(getString(R.string.error_invalid_password)); focusView = mPasswordView; cancel = true; } if (TextUtils.isEmpty(email)) { mEmailView.setError(getString(R.string.error_field_required)); focusView = mEmailView; cancel = true; } else if (!isEmailValid(email)) { mEmailView.setError(getString(R.string.error_invalid_email)); focusView = mEmailView; cancel = true; } if (cancel) { focusView.requestFocus(); } else { showProgress(true); mAuthTask = new UserLoginTask(email, password); mAuthTask.execute((Void) null); } } Faaaaaaaaaaaat Controller!!
8. Fat Controller is bad because... • Slow iteration • Ambiguous responsibilities • Off-by-one errors • Un-reproducible bugs
9. Unit testing lets you... • Faster execution • Clear division of roles • Chance to improve architecture
10. Is unit testing just enough?
11. No!! It just ensures it partially worked
12. See also... • EspressoςετίʔυͷಉظॲཧΛڀΊΔ • Day1 Room5 15:40 - • UIςετͷ࣮ߦ࣌ؒΛ୹ॖͤ͞Δํ๏ • Day2 Room2 18:30 -
13. anyway
14. JUnit4 and basic assertions
15. JUnit4 is... • A simple testing framework • Available for Android out-of-the-box • Still de-facto standard Moving Forward with JUnit 5 - Day2 Room5 10:30 - Check also
16. Assertions
17. Assertion is... • Assert something is something A rose is a rose is a rose is a rose... assertThat(1 + 1).isEqualTo(2); assertThat("Alice") .isNotEmpty() .isNotEqualTo("Bob");
18. Installation dependencies { testImplementation 'junit:junit:4.12' testImplementation 'com.squareup.assertj:assertj-android:1.2.0' } assertj-android lets you assert Android framework's code as well
19. Test target class InputChecker { boolean isValid(String text) { if (text.length() < 4) return false; if (!text.matches("[a-zA-Z0-9]+")) return false; return true; } } VERY SIMPLE input text checker
20. Create New Test Command + SHIFT + T
21. Create New Test
22. Create New Test
23. Types of test in Android • Local Unit Tests • Runs on JVM • src/test • Instrumented Tests • Runs with Device/Emulators • src/androidTest
24. Local Unit Tests: pros • Runs fast! • No device, emulator, android sdk
25. Local Unit Tests: cons • No REAL Android framework's code
26. • TRUE Android Test • Exactly the same behavior as production Instrumented Tests: pros
27. Instrumented Tests: cons • Runs slow! • Need device, emulator, android sdk
28. This session only cares Local Unit Tests
29. Test class public class InputCheckerTest { @Before public void setUp() throws Exception { } @Test public void isValid() throws Exception { } }
30. Test class public class InputCheckerTest { @Before public void setUp() throws Exception { } @Test public void isValid() throws Exception { } } Just naming convention
31. Test class public class InputCheckerTest { @Before public void setUp() throws Exception { } @Test public void isValid() throws Exception { } } Called at every test case
32. Test class public class InputCheckerTest { @Before public void setUp() throws Exception { } @Test public void isValid() throws Exception { } } This is a test case Write as many as you want
33. Test class public class InputCheckerTest { @Before public void setUp() throws Exception { }foo @Test public void isValid() throws Exception { }foo }foo
34. Test class public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); }foo @Test public void isValid() throws Exception { }foo }foo
35. Test class public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); } @Test public void isValid() throws Exception { } } Initialization codes here
36. Test class public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); }foo @Test public void isValid() throws Exception { }foo }foo
37. Test class public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); }foo @Test public void isValid() throws Exception { String input = "voodoo"; boolean actual = inputChecker.isValid(input); Assertions.assertThat(actual).isTrue(); }foo }foo
38. Test class public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); } @Test public void isValid() throws Exception { String input = "voodoo"; boolean actual = inputChecker.isValid(input); Assertions.assertThat(actual).isTrue(); } } Write your assertions
39. Test class public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); } @Test public void isValid() throws Exception { String input = "voodoo"; boolean actual = inputChecker.isValid(input); Assertions.assertThat(actual).isTrue(); } } what really is "actual"
40. Test class public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); } @Test public void isValid() throws Exception { String input = "voodoo"; boolean actual = inputChecker.isValid(input); Assertions.assertThat(actual).isTrue(); } } "expectation" what you expect it to be
41. Test class public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); } @Test public void isValid() throws Exception { String input = "voodoo"; boolean actual = inputChecker.isValid(input); Assertions.assertThat(actual).isTrue(); } } From AssertJ Many assertion methods available
42. Test class public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); } @Test public void isValid() throws Exception { String input = "voodoo"; boolean actual = inputChecker.isValid(input); Assertions.assertThat(actual).isTrue(); } }
43. Run tests Run single Run all or Passed!!!!
44. If it fails... reason why it failed failure... Fix and try again!!!
45. Congrats!!!
46. Assertions (AssertJ) • assertThat(all) • isEqualTo / isNotEqualTo • assertThat(String) • isEmpty / isNotEmpty • assertThat(Number) • isPositive / isNegative / isZero / isNotZero • isGreaterThan / isLessThan lots and lots and lots more
47. • assertThat(list) • contains / containsOnly / containsExactly Assertions (AssertJ) lots and lots and lots more List<String> strings = Arrays.asList("foo", "bar", "baz"); assertThat(strings).contains("bar"); same collection same collection and order
48. • http://joel-costigliola.github.io/assertj/ • https://github.com/square/assertj-android • https://qiita.com/opengl-8080/items/ b07307ab0d33422be9c5 AssertJ
49. Exceptions
50. Remember this... class InputChecker { boolean isValid(String text) { if (text.length() < 4) return false; if (!text.matches("[a-zA-Z0-9]+")) return false; return true; } }
51. Remember this... class InputChecker { boolean isValid(String text) { if (text.length() < 4) return false; if (!text.matches("[a-zA-Z0-9]+")) return false; return true; } } What if null... Let's try it anyway
52. Ouch!! @Test public void isValid() throws Exception { String input = null; boolean actual = inputChecker.isValid(input); assertThat(actual).isTrue(); }
53. Expected Exception @Test(expected = NullPointerException.class) public void isValid() throws Exception { String input = null; boolean actual = inputChecker.isValid(input); assertThat(actual).isTrue(); }
54. Expected Exception @Test(expected = NullPointerException.class) public void isValid() throws Exception { String input = null; boolean actual = inputChecker.isValid(input); assertThat(actual).isTrue(); }
55. Passed!! @Test(expected = NullPointerException.class) public void isValid() throws Exception { String input = null; boolean actual = inputChecker.isValid(input); assertThat(actual).isTrue(); }
56. Better yet... class InputChecker { boolean isValid(String text) { if (text.length() < 4) return false; if (!text.matches("[a-zA-Z0-9]+")) return false; return true; }foo }foo
57. Better yet... class InputChecker { boolean isValid(@NonNull String text) { if (text == null) throw new IllegalArgumentException("cannot be null"); if (text.length() < 4) return false; if (!text.matches("[a-zA-Z0-9]+")) return false; return true; }foo }foo
58. Better yet... class InputChecker { boolean isValid(@NonNull String text) { if (text == null) throw new IllegalArgumentException("cannot be null"); if (text.length() < 4) return false; if (!text.matches("[a-zA-Z0-9]+")) return false; return true; } }
59. Better yet... class InputChecker { boolean isValid(@NonNull String text) { if (text == null) throw new IllegalArgumentException("cannot be null"); if (text.length() < 4) return false; if (!text.matches("[a-zA-Z0-9]+")) return false; return true; } } Unit testing helps you refactoring!!
60. Way better!! @Test(expected = IllegalArgumentException.class) public void isValid() throws Exception { String input = null; boolean actual = inputChecker.isValid(input); assertThat(actual).isTrue(); }
61. Mock and spy with Mockito
62. Mock is... • A WHOLE imitation of a real object • Used to simulate the behavior of depending objects
63. Spy is... • A PARTIAL imitation of a real object • Used to simulate the behavior of depending objects
64. Test Doubles They are
65. Why you need mocks?
66. TweetRepository public class TweetRepository { private final LocalTweetDataSource localDataSource; public TweetRepository(LocalTweetDataSource localDataSource) { this.localDataSource = localDataSource; } public List<Tweet> getTimeline() { return localDataSource.getTimeline(); } }
67. TweetRepository public class TweetRepository { private final LocalTweetDataSource localDataSource; public TweetRepository(LocalTweetDataSource localDataSource) { this.localDataSource = localDataSource; } public List<Tweet> getTimeline() { return localDataSource.getTimeline(); } } depending on local data source
68. Data Source public class LocalTweetDataSource { public List<Tweet> getTimeline() { List<Tweet> tweets = new ArrayList<>(); // some local DB interaction // ..... return tweets; } }
69. Data Source public class LocalTweetDataSource { public List<Tweet> getTimeline() { List<Tweet> tweets = new ArrayList<>(); // some local DB interaction // ..... return tweets; } } Because it dose so many interactions with DB You don't wanna deal with all those messes!
70. TweetRepository public class TweetRepository { private final LocalTweetDataSource localDataSource; public TweetRepository(LocalTweetDataSource localDataSource) { this.localDataSource = localDataSource; } public List<Tweet> getTimeline() { return localDataSource.getTimeline(); } } You can replace this with simple mock
71. Mockito
72. Mockito is... • A simple mocking library • Most used one in Java and Android community
73. Installation dependencies { testImplementation 'org.mockito:mockito-inline:2.13.0' } mockito-inline lets you mock final class & methods this artifact may be integrated into default in the future but you can't mock static methods & constructors
74. Stubbing
75. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn( Arrays.asList( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ) );
76. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn( Arrays.asList( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ) );
77. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn( Arrays.asList( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ) );
78. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn( Arrays.asList( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ) ); mock instance
79. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn(); stub method
80. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn();
81. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn();
82. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn();
83. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn( );zz
84. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn( Arrays.asList( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ) );zz
85. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn( Arrays.asList( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ) );zz any item you wanna return
86. Stubbing import static org.mockito.Mockito.*; LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn( Arrays.asList( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ) );
87. Stubbing private TweetRepository tweetRepository; @Before public void setUp() throws Exception { LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn( Arrays.asList( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ) ); tweetRepository = new TweetRepository(localDataSource); }
88. Stubbing private TweetRepository tweetRepository; @Before public void setUp() throws Exception { LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn( Arrays.asList( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ) ); tweetRepository = new TweetRepository(localDataSource); }
89. Stubbing @Test public void getTimeline() throws Exception { List<Tweet> tweets = tweetRepository.getTimeline(); assertThat(tweets) .isNotEmpty() .hasSize(3) .containsExactly( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ); }
90. Stubbing @Test public void getTimeline() throws Exception { List<Tweet> tweets = tweetRepository.getTimeline(); assertThat(tweets) .isNotEmpty() .hasSize(3) .containsExactly( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ); }
91. Stubbing @Test public void getTimeline() throws Exception { List<Tweet> tweets = tweetRepository.getTimeline(); assertThat(tweets) .isNotEmpty() .hasSize(3) .containsExactly( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ); }
92. Stubbing @Test public void getTimeline() throws Exception { List<Tweet> tweets = tweetRepository.getTimeline(); assertThat(tweets) .isNotEmpty() .hasSize(3) .containsExactly( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ); }
93. Stubbing @Test public void getTimeline() throws Exception { List<Tweet> tweets = tweetRepository.getTimeline(); assertThat(tweets) .isNotEmpty() .hasSize(3) .containsExactly( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz") ); } pass!!
94. Spying
95. Spying is... • Stub methods can be added on a REAL object That means spied objects acts EXACTLY the same as real objects unless stubbed
96. Spying List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) ); verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt());
97. Spying List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) ); verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt()); normal ArrayList
98. Spying List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) ); verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt()); wrap with spy()
99. Spying List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) ); verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt()); things you typically to with List
100. Verify • Check the interactions with mock/spy mocks/spies will remember all interactions
101. Verify List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify( );abc verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt());
102. Verify List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) );abc verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt());
103. Verify List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) );abc verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt());
104. Verify List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) );abc verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt());
105. Verify List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) );abc verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt());
106. Verify List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) );abc verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt());
107. Verify List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) );abc verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt()); notice!
108. Verify List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) );abc verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt());
109. Verify List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) ); verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt());
110. Verify List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) ); verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt()); no interaction
111. Verify List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); verify(strings, times(1)).addAll( eq(Arrays.asList("pop", "team", "epic")) ); verify(strings, never()).add(eq("pop")); verify(strings, never()).get(anyInt()); argument matcher
112. Argument matchers • eq(T) • anyString() • anyInt() • any() • any(Class<T>) • nullable(Class<T>) null or T including null
113. Stubbing with callbacks List<String> strings = spy(new ArrayList<String>()); String[] array = {"pop", "team", "epic"}; strings.addAll(asList(array)); when(strings.get(anyInt())).thenAnswer(invocation -> { Object[] arguments = invocation.getArguments(); int index = (int) arguments[0]; if (index < array.length) return array[index]; return "something-else"; }); String got = strings.get(123); assertThat(got).isEqualTo("something-else"); if you wanna change return val according to the arguments
114. Stubbing with callbacks List<String> strings = spy(new ArrayList<String>()); String[] array = {"pop", "team", "epic"}; strings.addAll(asList(array)); when().thenAnswer(invocation -> { });
115. Stubbing with callbacks List<String> strings = spy(new ArrayList<String>()); String[] array = {"pop", "team", "epic"}; strings.addAll(asList(array)); when(strings.get(anyInt())).thenAnswer(invocation -> { Object[] arguments = invocation.getArguments(); int index = (int) arguments[0]; if (index < array.length) return array[index]; return "something-else"; }); String got = strings.get(123); assertThat(got).isEqualTo("something-else");
116. Stubbing with callbacks List<String> strings = spy(new ArrayList<String>()); String[] array = {"pop", "team", "epic"}; strings.addAll(asList(array)); when(strings.get(anyInt())).thenAnswer(invocation -> { Object[] arguments = invocation.getArguments(); int index = (int) arguments[0]; if (index < array.length) return array[index]; return "something-else"; }); String got = strings.get(123); assertThat(got).isEqualTo("something-else");
117. Stubbing with callbacks List<String> strings = spy(new ArrayList<String>()); String[] array = {"pop", "team", "epic"}; strings.addAll(asList(array)); when(strings.get(anyInt())).thenAnswer(invocation -> { Object[] arguments = invocation.getArguments(); int index = (int) arguments[0]; if (index < array.length) return array[index]; return "something-else"; }); String got = strings.get(123); assertThat(got).isEqualTo("something-else");
118. Stubbing with callbacks List<String> strings = spy(new ArrayList<String>()); String[] array = {"pop", "team", "epic"}; strings.addAll(asList(array)); when(strings.get(anyInt())).thenAnswer(invocation -> { Object[] arguments = invocation.getArguments(); int index = (int) arguments[0]; if (index < array.length) return array[index]; return "something-else"; }); String got = strings.get(123); assertThat(got).isEqualTo("something-else"); whatever logic you like
119. Stubbing with callbacks List<String> strings = spy(new ArrayList<String>()); String[] array = {"pop", "team", "epic"}; strings.addAll(asList(array)); when(strings.get(anyInt())).thenAnswer(invocation -> { Object[] arguments = invocation.getArguments(); int index = (int) arguments[0]; if (index < array.length) return array[index]; return "something-else"; }); String got = strings.get(123); assertThat(got).isEqualTo("something-else"); Don't abuse this since it spoils simplicity
120. Stubbing spy method
121. doReturn List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); when(strings.get(3)).thenReturn("foo"); when().thenReturn() is almost always useful
122. doReturn List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); when(strings.get(3)).thenReturn("foo"); 0 1 2 Because this is a spy, not mock, List#get() is evaluated first that causes an Exception
123. doReturn List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); doReturn("foo").when(strings).get(3); String got = strings.get(3); Assertions.assertThat(got).isEqualTo("foo");
124. doReturn List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); doReturn("foo").when(strings).get(3); String got = strings.get(3); Assertions.assertThat(got).isEqualTo("foo");
125. doReturn List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); doReturn("foo").when(strings).get(3); String got = strings.get(3); Assertions.assertThat(got).isEqualTo("foo");
126. doReturn List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); doReturn("foo").when(strings).get(3); String got = strings.get(3); Assertions.assertThat(got).isEqualTo("foo");
127. doReturn List<String> strings = spy(new ArrayList<String>()); strings.addAll(Arrays.asList("pop", "team", "epic")); strings.forEach(System.out::println); doReturn("foo").when(strings).get(3); String got = strings.get(3); Assertions.assertThat(got).isEqualTo("foo"); This works well!
128. Stubbing void method
129. doThrow / doNothing List<String> strings = spy(new ArrayList<String>()); doThrow(new IllegalStateException()).when(strings).clear(); strings.clear();
130. doThrow / doNothing List<String> strings = spy(new ArrayList<String>()); doThrow(new IllegalStateException()).when(strings).clear(); strings.clear();
131. doThrow / doNothing List<String> strings = spy(new ArrayList<String>()); doThrow(new IllegalStateException()).when(strings).clear(); strings.clear();
132. doThrow / doNothing List<String> strings = spy(new ArrayList<String>()); doThrow(new IllegalStateException()).when(strings).clear(); strings.clear();
133. doThrow / doNothing List<String> strings = spy(new ArrayList<String>()); doThrow(new IllegalStateException()).when(strings).clear(); strings.clear();
134. doThrow / doNothing List<String> strings = spy(new ArrayList<String>()); doThrow(new IllegalStateException()).when(strings).clear(); strings.clear();
135. doThrow / doNothing List<String> strings = spy(new ArrayList<String>()); doThrow(new IllegalStateException()).when(strings).clear(); doNothing().when(strings).clear(); strings.clear();
136. doThrow / doNothing List<String> strings = spy(new ArrayList<String>()); doThrow(new IllegalStateException()).when(strings).clear(); doNothing().when(strings).clear(); strings.clear();
137. doThrow / doNothing List<String> strings = spy(new ArrayList<String>()); doThrow(new IllegalStateException()).when(strings).clear(); doNothing().when(strings).clear(); strings.clear(); pass!!
138. • http://site.mockito.org/ • http://static.javadoc.io/org.mockito/mockito-core/ 2.13.0/org/mockito/Mockito.html#0 Mockito REALLY HELPFUL!!
139. Robolectric for framework's code
140. InputChecker class InputChecker { boolean isValid(@NonNull String text) { if (text == null) throw new IllegalArgumentException("cannot be null"); if (text.length() < 4) return false; if (!text.matches("[a-zA-Z0-9]+")) return false; return true; } }
141. InputChecker class InputChecker { boolean isValid(@NonNull String text) { if (TextUtils.isEmpty(text)) throw new IllegalArgumentException("cannot be blank"); if (text.length() < 4) return false; if (!text.matches("[a-zA-Z0-9]+")) return false; return true; } }
142. InputChecker class InputChecker { boolean isValid(@NonNull String text) { if (TextUtils.isEmpty(text)) throw new IllegalArgumentException("cannot be blank"); if (text.length() < 4) return false; if (!text.matches("[a-zA-Z0-9]+")) return false; return true; } } android.text.TextUtils
143. InputCheckerTest public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); } @Test public void isValid() throws Exception { String input = "voodoo"; boolean actual = inputChecker.isValid(input); assertThat(actual).isTrue(); } }
144. InputCheckerTest Basically, Android framework's code cannot be executed on JVM tests
145. app/build.gradle android { testOptions { unitTests.returnDefaultValues = true } } notice: this setting just return the default value @Test isValid() passes successfully
146. InputCheckerTest public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); } @Test(expected = IllegalArgumentException.class) public void isValid_fails_with_blank() throws Exception { String input = ""; inputChecker.isValid(input); } } Add a test case that checks blank input
147. InputCheckerTest public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); } @Test(expected = IllegalArgumentException.class) public void isValid_fails_with_blank() throws Exception { String input = ""; inputChecker.isValid(input); } } Expected exception was not thrown! This is because of the "default value" from test options
148. Robolectric
149. Robolectric is... • "A unit test framework that de-fangs the Android SDK jar so you can test-drive the development of your Android app." • "Tests run inside the JVM on your workstation in seconds." quoted from the official site
150. testImplementation "org.robolectric:robolectric:3.6.1" android { testOptions { unitTests { includeAndroidResources = true } } } Installation remove: unitTests.returnDefaultValues = true
151. InputCheckerTest @RunWith(RobolectricTestRunner.class) public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); } @Test(expected = IllegalArgumentException.class) public void isValid_fails_with_blank() throws Exception { String input = ""; inputChecker.isValid(input); } }
152. InputCheckerTest @RunWith(RobolectricTestRunner.class) public class InputCheckerTest { private InputChecker inputChecker; @Before public void setUp() throws Exception { inputChecker = new InputChecker(); } @Test(expected = IllegalArgumentException.class) public void isValid_fails_with_blank() throws Exception { String input = ""; inputChecker.isValid(input); } } Just add this!!
153. Context in Robolectric @RunWith(RobolectricTestRunner.class) public class SQLiteTest { private SQLiteDatabase db; @Before public void setUp() throws Exception { Context context = RuntimeEnvironment.application.getApplicationContext(); SQLiteOpenHelper helper = new MySQLiteOpenHelper(context); db = helper.getWritableDatabase(); } @Test public void test_db() throws Exception { // do the stuff } }
154. Context in Robolectric @RunWith(RobolectricTestRunner.class) public class SQLiteTest { private SQLiteDatabase db; @Before public void setUp() throws Exception { Context context = RuntimeEnvironment.application.getApplicationContext(); SQLiteOpenHelper helper = new MySQLiteOpenHelper(context); db = helper.getWritableDatabase(); } @Test public void test_db() throws Exception { // do the stuff } } Really handy to use!!
155. • http://robolectric.org/ • http://robolectric.org/getting-started/ • http://robolectric.org/extending/ Robolectric One thing you have to notice about Robolectric is It just mimics the framework's behavior, not the real one
156. Unit Testing SQLite
157. • Robolectric simulates SQLite out-of-the-box!! • You can use traditional SQLiteOpenHelper • You can also use the latest Room Persistence Library Unit Testing SQLite
158. Room Persistence Library dependencies { implementation "android.arch.persistence.room:runtime:1.0.0" annotationProcessor "android.arch.persistence.room:compiler:1.0.0" }
159. Room Persistence Library @Entity public class User { @PrimaryKey private int uid; @ColumnInfo(name = "first_name") private String firstName; @ColumnInfo(name = "last_name") private String lastName; public User(String firstName, String lastName) { this.firstName = firstName; this.lastName = lastName; } // getters & setters } Entity
160. Room Persistence Library @Dao public interface UserDao { @Query("SELECT * FROM user") List<User> getAll(); @Query("SELECT * FROM user WHERE uid IN (:userIds)") List<User> loadAllByIds(int[] userIds); @Query("SELECT * FROM user WHERE first_name LIKE :first AND " + "last_name LIKE :last LIMIT 1") User findByName(String first, String last); @Insert void insertAll(User... users); @Delete void delete(User user); } Dao
161. Room Persistence Library @Database(entities = {User.class}, version = 1) public abstract class AppDatabase extends RoomDatabase { public abstract UserDao userDao(); } Database
162. Room Persistence Library public class UserManager { private final String DB_NAME = "sample_app"; private final AppDatabase db; public UserManager(@NonNull Context context) { db = Room.databaseBuilder(context.getApplicationContext(), AppDatabase.class, DB_NAME) .allowMainThreadQueries() .build(); } public void insertUser(@NonNull User user) { db.userDao().insertAll(user); } public List<User> getUsers() { return db.userDao().getAll(); } } Business Logic
163. Room Persistence Library public class UserManager { private final String DB_NAME = "sample_app"; private final AppDatabase db; public UserManager(@NonNull Context context) { db = Room.databaseBuilder(context.getApplicationContext(), AppDatabase.class, DB_NAME) .allowMainThreadQueries() .build(); } public void insertUser(@NonNull User user) { db.userDao().insertAll(user); } public List<User> getUsers() { return db.userDao().getAll(); } } Business Logic just for demo's convenience
164. Room Persistence Library public class UserManager { private final String DB_NAME = "sample_app"; private final AppDatabase db; public UserManager(@NonNull Context context) { db = Room.databaseBuilder(context.getApplicationContext(), AppDatabase.class, DB_NAME) .allowMainThreadQueries() .build(); } public void insertUser(@NonNull User user) { db.userDao().insertAll(user); } public List<User> getUsers() { return db.userDao().getAll(); } } Business Logic delegate
165. Room Persistence Library public class UserManager { private final String DB_NAME = "sample_app"; private final AppDatabase db; public UserManager(@NonNull Context context) { db = Room.databaseBuilder(context.getApplicationContext(), AppDatabase.class, DB_NAME) .allowMainThreadQueries() .build(); } public void insertUser(@NonNull User user) { db.userDao().insertAll(user); } public List<User> getUsers() { return db.userDao().getAll(); } } Business Logic delegate
166. Room Persistence Library @RunWith(RobolectricTestRunner.class) public class UserManagerTest { private UserManager userManager; @Before public void setUp() throws Exception { Context context = RuntimeEnvironment.application.getApplicationContext(); userManager = new UserManager(context); } @Test public void insert_and_get() throws Exception { List<User> users = userManager.getUsers(); assertThat(users).isEmpty(); userManager.insertUser(new User("Fumihiko", "Shiroyama")); users = userManager.getUsers(); assertThat(users) .isNotEmpty() .hasSize(1); } }
167. Room Persistence Library @RunWith(RobolectricTestRunner.class) public class UserManagerTest { private UserManager userManager; @Before public void setUp() throws Exception { Context context = RuntimeEnvironment.application.getApplicationContext(); userManager = new UserManager(context); } @Test public void insert_and_get() throws Exception { List<User> users = userManager.getUsers(); assertThat(users).isEmpty(); userManager.insertUser(new User("Fumihiko", "Shiroyama")); users = userManager.getUsers(); assertThat(users) .isNotEmpty() .hasSize(1); } }
168. Room Persistence Library @RunWith(RobolectricTestRunner.class) public class UserManagerTest { private UserManager userManager; @Before public void setUp() throws Exception { Context context = RuntimeEnvironment.application.getApplicationContext(); userManager = new UserManager(context); } @Test public void insert_and_get() throws Exception { List<User> users = userManager.getUsers(); assertThat(users).isEmpty(); userManager.insertUser(new User("Fumihiko", "Shiroyama")); users = userManager.getUsers(); assertThat(users) .isNotEmpty() .hasSize(1); } }
169. Room Persistence Library @RunWith(RobolectricTestRunner.class) public class UserManagerTest { private UserManager userManager; @Before public void setUp() throws Exception { Context context = RuntimeEnvironment.application.getApplicationContext(); userManager = new UserManager(context); } @Test public void insert_and_get() throws Exception { List<User> users = userManager.getUsers(); assertThat(users).isEmpty(); userManager.insertUser(new User("Fumihiko", "Shiroyama")); users = userManager.getUsers(); assertThat(users) .isNotEmpty() .hasSize(1); } }
170. Room Persistence Library @RunWith(RobolectricTestRunner.class) public class UserManagerTest { private UserManager userManager; @Before public void setUp() throws Exception { Context context = RuntimeEnvironment.application.getApplicationContext(); userManager = new UserManager(context); } @Test public void insert_and_get() throws Exception { List<User> users = userManager.getUsers(); assertThat(users).isEmpty(); userManager.insertUser(new User("Fumihiko", "Shiroyama")); users = userManager.getUsers(); assertThat(users) .isNotEmpty() .hasSize(1); } }
171. Room Persistence Library @RunWith(RobolectricTestRunner.class) public class UserManagerTest { private UserManager userManager; @Before public void setUp() throws Exception { Context context = RuntimeEnvironment.application.getApplicationContext(); userManager = new UserManager(context); } @Test public void insert_and_get() throws Exception { List<User> users = userManager.getUsers(); assertThat(users).isEmpty(); userManager.insertUser(new User("Fumihiko", "Shiroyama")); users = userManager.getUsers(); assertThat(users) .isNotEmpty() .hasSize(1); } }
172. Room Persistence Library @RunWith(RobolectricTestRunner.class) public class UserManagerTest { private UserManager userManager; @Before public void setUp() throws Exception { Context context = RuntimeEnvironment.application.getApplicationContext(); userManager = new UserManager(context); } @Test public void insert_and_get() throws Exception { List<User> users = userManager.getUsers(); assertThat(users).isEmpty(); userManager.insertUser(new User("Fumihiko", "Shiroyama")); users = userManager.getUsers(); assertThat(users) .isNotEmpty() .hasSize(1); } } DB & table's data are reset automatically
173. Room Persistence Library • https://developer.android.com/topic/ libraries/architecture/room.html • https://developer.android.com/topic/ libraries/architecture/adding- components.html • https://developer.android.com/training/ data-storage/room/index.html
174. Unit Testing asynchronous code
175. Testing async code • Testing asynchronous code is not always easy I'd introduce the very basic concept of it!
176. Synchronous call interface Fetcher<T> { T fetch(); class StringFetcher implements Fetcher<String> { @Override public String fetch() { return "OK"; } } } Think of a synchronous API call over internet
177. Simple callback Callback interfaces interface OnSuccess<T> { void onSuccess(T result); } interface OnFailure { void onFailure(Exception e); }
178. Asynchronous call class AsyncFetcher<T> { private final Fetcher<T> fetcher; AsyncFetcher(Fetcher<T> fetcher) { this.fetcher = fetcher; } void fetch(OnSuccess<T> onSuccess, OnFailure onFailure) { new Thread(() -> { try { Thread.sleep(1000L); onSuccess.onSuccess(fetcher.fetch()); } catch (Exception e) { onFailure.onFailure(e); } }).start(); } } Think of an asynchronous API call over internet
179. Asynchronous call class AsyncFetcher<T> { private final Fetcher<T> fetcher; AsyncFetcher(Fetcher<T> fetcher) { this.fetcher = fetcher; } void fetch(OnSuccess<T> onSuccess, OnFailure onFailure) { new Thread(() -> { try { Thread.sleep(1000L); onSuccess.onSuccess(fetcher.fetch()); } catch (Exception e) { onFailure.onFailure(e); } }).start(); } }
180. Asynchronous call class AsyncFetcher<T> { private final Fetcher<T> fetcher; AsyncFetcher(Fetcher<T> fetcher) { this.fetcher = fetcher; } void fetch(OnSuccess<T> onSuccess, OnFailure onFailure) { new Thread(() -> { try { Thread.sleep(1000L); onSuccess.onSuccess(fetcher.fetch()); } catch (Exception e) { onFailure.onFailure(e); } }).start(); } }
181. Asynchronous call class AsyncFetcher<T> { private final Fetcher<T> fetcher; AsyncFetcher(Fetcher<T> fetcher) { this.fetcher = fetcher; } void fetch(OnSuccess<T> onSuccess, OnFailure onFailure) { new Thread(() -> { try { Thread.sleep(1000L); onSuccess.onSuccess(fetcher.fetch()); } catch (Exception e) { onFailure.onFailure(e); } }).start(); } } Executed on a different thread
182. Asynchronous call class AsyncFetcher<T> { private final Fetcher<T> fetcher; AsyncFetcher(Fetcher<T> fetcher) { this.fetcher = fetcher; } void fetch(OnSuccess<T> onSuccess, OnFailure onFailure) { new Thread(() -> { try { Thread.sleep(1000L); onSuccess.onSuccess(fetcher.fetch()); } catch (Exception e) { onFailure.onFailure(e); } }).start(); } } time intensive task
183. Asynchronous call class AsyncFetcher<T> { private final Fetcher<T> fetcher; AsyncFetcher(Fetcher<T> fetcher) { this.fetcher = fetcher; } void fetch(OnSuccess<T> onSuccess, OnFailure onFailure) { new Thread(() -> { try { Thread.sleep(1000L); onSuccess.onSuccess(fetcher.fetch()); } catch (Exception e) { onFailure.onFailure(e); } }).start(); } } Callbacks
184. Asynchronous Test public class AsyncFetcherTest { private Fetcher<String> fetcher; private AsyncFetcher<String> asyncFetcher; @Before public void setUp() throws Exception { fetcher = spy(new Fetcher.StringFetcher()); asyncFetcher = new AsyncFetcher<>(fetcher); } @Test public void fetch_success() throws Exception { asyncFetcher.fetch(); } }
185. Asynchronous Test public class AsyncFetcherTest { private Fetcher<String> fetcher; private AsyncFetcher<String> asyncFetcher; @Before public void setUp() throws Exception { fetcher = spy(new Fetcher.StringFetcher()); asyncFetcher = new AsyncFetcher<>(fetcher); } @Test public void fetch_success() throws Exception { asyncFetcher.fetch(); } }
186. Asynchronous Test public class AsyncFetcherTest { private Fetcher<String> fetcher; private AsyncFetcher<String> asyncFetcher; @Before public void setUp() throws Exception { fetcher = spy(new Fetcher.StringFetcher()); asyncFetcher = new AsyncFetcher<>(fetcher); } @Test public void fetch_success() throws Exception { asyncFetcher.fetch(); } } How do I write this test?
187. Asynchronous Test @Test public void fetch_success() throws Exception { asyncFetcher.fetch( result -> { assertThat(result).isEqualTo("OK"); log("async: ok"); }, e -> log("async: ng") ); log("fetch_success: end"); }
188. Asynchronous Test @Test public void fetch_success() throws Exception { asyncFetcher.fetch( result -> { assertThat(result).isEqualTo("OK"); log("async: ok"); }, e -> log("async: ng") ); log("fetch_success: end"); } success
189. Asynchronous Test @Test public void fetch_success() throws Exception { asyncFetcher.fetch( result -> { assertThat(result).isEqualTo("OK"); log("async: ok"); }, e -> log("async: ng") ); log("fetch_success: end"); } failure
190. Asynchronous Test @Test public void fetch_failure() throws Exception { doThrow(new RuntimeException("NG")).when(fetcher).fetch(); asyncFetcher.fetch( result -> log("async: ok"), e -> { assertThat(e.getMessage()).isEqualTo("NG"); log("async: ng"); } ); log("fetch_failure: end"); }
191. Asynchronous Test @Test public void fetch_failure() throws Exception { doThrow(new RuntimeException("NG")).when(fetcher).fetch(); asyncFetcher.fetch( result -> log("async: ok"), e -> { assertThat(e.getMessage()).isEqualTo("NG"); log("async: ng"); } ); log("fetch_failure: end"); } stub failure
192. Asynchronous Test Callback is NOT actually called!!! Execution seems successful...but wait?
193. Asynchronous Test private CountDownLatch latch; @Before public void setUp() throws Exception { fetcher = spy(new Fetcher.StringFetcher()); asyncFetcher = new AsyncFetcher<>(fetcher); latch = new CountDownLatch(1); }
194. Asynchronous Test Acts like an ON/OFF latch private CountDownLatch latch; @Before public void setUp() throws Exception { fetcher = spy(new Fetcher.StringFetcher()); asyncFetcher = new AsyncFetcher<>(fetcher); latch = new CountDownLatch(1); }
195. Asynchronous Test @Test public void fetch_success() throws Exception { asyncFetcher.fetch( result -> { assertThat(result).isEqualTo("OK"); log("async: ok"); latch.countDown(); }, e -> log("async: ng") ); latch.await(); log("fetch_success: end"); }
196. Asynchronous Test @Test public void fetch_success() throws Exception { asyncFetcher.fetch( result -> { assertThat(result).isEqualTo("OK"); log("async: ok"); latch.countDown(); }, e -> log("async: ng") ); latch.await(); log("fetch_success: end"); }
197. Asynchronous Test @Test public void fetch_success() throws Exception { asyncFetcher.fetch( result -> { assertThat(result).isEqualTo("OK"); log("async: ok"); latch.countDown(); }, e -> log("async: ng") ); latch.await(); log("fetch_success: end"); } Test execution awaits here
198. Asynchronous Test @Test public void fetch_success() throws Exception { asyncFetcher.fetch( result -> { assertThat(result).isEqualTo("OK"); log("async: ok"); latch.countDown(); }, e -> log("async: ng") ); latch.await(); log("fetch_success: end"); } Opens the latch and test goes again
199. Asynchronous Test @Test public void fetch_failure() throws Exception { doThrow(new RuntimeException("NG")).when(fetcher).fetch(); asyncFetcher.fetch( result -> log("async: ok"), e -> { assertThat(e.getMessage()).isEqualTo("NG"); log("async: ng"); latch.countDown(); } ); latch.await(); log("fetch_failure: end"); }
200. Asynchronous Test @Test public void fetch_failure() throws Exception { doThrow(new RuntimeException("NG")).when(fetcher).fetch(); asyncFetcher.fetch( result -> log("async: ok"), e -> { assertThat(e.getMessage()).isEqualTo("NG"); log("async: ng"); latch.countDown(); } ); latch.await(); log("fetch_failure: end"); } The same implementation as success
201. Asynchronous Test Callback is properly called!!! Log message seems correct!!
202. Additional info... • MockWebServer for OkHttp • TestSubscriber for RxJava • https://speakerdeck.com/srym/ hayaiyasuiumai-sutatoatupudemoshi-eru- retrofit-plus-rxjava-deshun-jian- apikutukinguresipi?slide=17 Check this slide & sample project
203. Best practices and tips
204. Best practices and tips • Use interface at the structural boundary • Use DI pattern for testability • Static is EVIL • Don't be a Mad Tester
205. Use interface at the structural boundary
206. Repository pattern public class TweetRepository { private final LocalTweetDataSource localDataSource; public TweetRepository(LocalTweetDataSource localDataSource) { this.localDataSource = localDataSource; } public List<Tweet> getTimeline() { return localDataSource.getTimeline(); } }
207. Repository pattern public class LocalTweetDataSource { public List<Tweet> getTimeline() { List<Tweet> tweets = new ArrayList<>(); // some local DB interaction return tweets; } } Concrete data source
208. Repository pattern public interface LocalTweetDataSource { List<Tweet> getTimeline(); class SQLiteTweetDataSource implements LocalTweetDataSource { @Override public List<Tweet> getTimeline() { List<Tweet> tweets = new ArrayList<>(); // some local DB interaction return tweets; } } class MockTweetDataSource implements LocalTweetDataSource { @Override public List<Tweet> getTimeline() { return Arrays.asList(/* some mock data */); } } }
209. Repository pattern public interface LocalTweetDataSource { List<Tweet> getTimeline(); class SQLiteTweetDataSource implements LocalTweetDataSource { @Override public List<Tweet> getTimeline() { List<Tweet> tweets = new ArrayList<>(); // some local DB interaction return tweets; } } class MockTweetDataSource implements LocalTweetDataSource { @Override public List<Tweet> getTimeline() { return Arrays.asList(/* some mock data */); } } }
210. Repository pattern public interface LocalTweetDataSource { List<Tweet> getTimeline(); class SQLiteTweetDataSource implements LocalTweetDataSource { @Override public List<Tweet> getTimeline() { List<Tweet> tweets = new ArrayList<>(); // some local DB interaction return tweets; } } class MockTweetDataSource implements LocalTweetDataSource { @Override public List<Tweet> getTimeline() { return Arrays.asList(/* some mock data */); } } } Concrete data source with real DB interactions
211. Repository pattern public interface LocalTweetDataSource { List<Tweet> getTimeline(); class SQLiteTweetDataSource implements LocalTweetDataSource { @Override public List<Tweet> getTimeline() { List<Tweet> tweets = new ArrayList<>(); // some local DB interaction return tweets; } } class MockTweetDataSource implements LocalTweetDataSource { @Override public List<Tweet> getTimeline() { return Arrays.asList(/* some mock data */); } } } mock data source just for tests
212. Repository pattern public class TweetRepositoryTest { private TweetRepository tweetRepository; @Before public void setUp() throws Exception { LocalTweetDataSource localDataSource = mock(LocalTweetDataSource.class); when(localDataSource.getTimeline()).thenReturn( Arrays.asList( Tweet.bodyOf("foo"), Tweet.bodyOf("bar"), Tweet.bodyOf("baz"))); tweetRepository = new TweetRepository(localDataSource); } }
213. Repository pattern public class TweetRepositoryTest { private TweetRepository tweetRepository; @Before public void setUp() throws Exception { LocalTweetDataSource localDataSource = new LocalTweetDataSource.MockTweetDataSource(); tweetRepository = new TweetRepository(localDataSource); } } You can even get rid of Mockito dependency
214. Use DI pattern for testability
215. Use DI pattern public class TweetRepository { private final LocalTweetDataSource localDataSource; public TweetRepository() { this.localDataSource = new LocalTweetDataSource.SQLiteTweetDataSource(); } public List<Tweet> getTimeline() { return localDataSource.getTimeline(); } }
216. Use DI pattern public class TweetRepository { private final LocalTweetDataSource localDataSource; public TweetRepository() { this.localDataSource = new LocalTweetDataSource.SQLiteTweetDataSource(); } public List<Tweet> getTimeline() { return localDataSource.getTimeline(); } } mocking field is painful!!
217. Use DI pattern public class TweetRepository { private final LocalTweetDataSource localDataSource; public TweetRepository() { this.localDataSource = new LocalTweetDataSource.SQLiteTweetDataSource(); } public List<Tweet> getTimeline() { return localDataSource.getTimeline(); } }
218. Use DI pattern public class TweetRepository { private final LocalTweetDataSource localDataSource; public TweetRepository(LocalTweetDataSource localDataSource) { this.localDataSource = localDataSource; } public List<Tweet> getTimeline() { return localDataSource.getTimeline(); } }
219. Use DI pattern public class TweetRepository { private final LocalTweetDataSource localDataSource; public TweetRepository(LocalTweetDataSource localDataSource) { this.localDataSource = localDataSource; } public List<Tweet> getTimeline() { return localDataSource.getTimeline(); } } Putting dependency from outer
220. Use DI pattern • This is so-called DI pattern • DI pattern does NOT have to use DI library • DI library (e.g. Dagger2) is useful though e.g. Factory Pattern
221. Static is EVIL
222. Static is EVIL because... • Static has global scope • Mockito cannot mock static • Static is practically unnecessary This may cause order dependent bugs
223. Static is practically unnecessary @Singleton public class TweetRepository { private final LocalTweetDataSource localDataSource; @Inject public TweetRepository(LocalTweetDataSource localDataSource) { this.localDataSource = localDataSource; } public List<Tweet> getTimeline() { return localDataSource.getTimeline(); } }
224. Static is practically unnecessary @Singleton public class TweetRepository { private final LocalTweetDataSource localDataSource; @Inject public TweetRepository(LocalTweetDataSource localDataSource) { this.localDataSource = localDataSource; } public List<Tweet> getTimeline() { return localDataSource.getTimeline(); } } Use Dagger's annotations for handy singleton
225. Don't be a Mad Tester
226. Don't be a Mad Tester • Avoid to test EVERYTHING • Unit tests are NOT perfect • Gain maximum with minimum investment! Enjoy your test life!!!
227. Thank you for listening! • All illustrations by www.irasutoya.com • Special Thanks to @sumio_tym, @numa08 • Get the slides: https://goo.gl/ju66No • Get the materials: https://goo.gl/R5kBeN