1 files changed, 190 insertions, 0 deletions
diff --git a/chromium/base/android/junit/src/org/chromium/base/supplier/ObservableSupplierImplTest.java b/chromium/base/android/junit/src/org/chromium/base/supplier/ObservableSupplierImplTest.java
new file mode 100644
index 00000000000..7b19a1aabb8
--- /dev/null
+++ b/chromium/base/android/junit/src/org/chromium/base/supplier/ObservableSupplierImplTest.java
@@ -0,0 +1,190 @@
+// Copyright 2019 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.base.supplier;
+
+import android.os.Handler;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.annotation.Config;
+
+import org.chromium.base.Callback;
+import org.chromium.base.test.BaseRobolectricTestRunner;
+
+/**
+ * Unit tests for {@link ObservableSupplierImpl}.
+ */
+@RunWith(BaseRobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class ObservableSupplierImplTest {
+    private static final String TEST_STRING_1 = "Test";
+    private static final String TEST_STRING_2 = "Test2";
+
+    private int mCallCount;
+    private String mLastSuppliedString;
+    private ObservableSupplierImpl<String> mSupplier = new ObservableSupplierImpl<>();
+
+    @Test
+    public void testObserverNotification_SetMultiple() {
+        Callback<String> supplierObserver = result -> {
+            mCallCount++;
+            mLastSuppliedString = result;
+        };
+
+        mSupplier.addObserver(supplierObserver);
+        checkState(0, null, null, "before setting first string.");
+
+        mSupplier.set(TEST_STRING_1);
+        checkState(1, TEST_STRING_1, TEST_STRING_1, "after setting first string.");
+
+        mSupplier.set(TEST_STRING_2);
+        checkState(2, TEST_STRING_2, TEST_STRING_2, "after setting second string.");
+
+        mSupplier.set(null);
+        checkState(3, null, null, "after setting third string.");
+    }
+
+    @Test
+    public void testObserverNotification_SetSame() {
+        Callback<String> supplierObserver = result -> {
+            mCallCount++;
+            mLastSuppliedString = result;
+        };
+
+        mSupplier.addObserver(supplierObserver);
+        checkState(0, null, null, "before setting first string.");
+
+        mSupplier.set(TEST_STRING_1);
+        checkState(1, TEST_STRING_1, TEST_STRING_1, "after setting first string.");
+
+        mSupplier.set(TEST_STRING_1);
+        checkState(1, TEST_STRING_1, TEST_STRING_1, "after resetting first string.");
+    }
+
+    @Test
+    public void testObserverNotification_RemoveObserver() {
+        Callback<String> supplierObserver = result -> {
+            mCallCount++;
+            mLastSuppliedString = result;
+        };
+
+        mSupplier.addObserver(supplierObserver);
+        checkState(0, null, null, "before setting first string.");
+
+        mSupplier.set(TEST_STRING_1);
+        checkState(1, TEST_STRING_1, TEST_STRING_1, "after setting first string.");
+
+        mSupplier.removeObserver(supplierObserver);
+
+        mSupplier.set(TEST_STRING_2);
+        checkState(1, TEST_STRING_1, TEST_STRING_2, "after setting second string.");
+    }
+
+    @Test
+    public void testObserverNotification_RegisterObserverAfterSet() {
+        Handler handler = new Handler();
+        handler.post(() -> {
+            mSupplier.set(TEST_STRING_1);
+            checkState(0, null, TEST_STRING_1, "after setting first string.");
+
+            Callback<String> supplierObserver = new Callback<String>() {
+                @Override
+                public void onResult(String result) {
+                    mCallCount++;
+                    mLastSuppliedString = result;
+                }
+            };
+
+            mSupplier.addObserver(supplierObserver);
+
+            checkState(0, null, TEST_STRING_1, "after setting observer.");
+        });
+
+        handler.post(() -> checkState(1, TEST_STRING_1, TEST_STRING_1, "in second message loop."));
+    }
+
+    @Test
+    public void testObserverNotification_RegisterObserverAfterSetThenSetAgain() {
+        Handler handler = new Handler();
+        handler.post(() -> {
+            mSupplier.set(TEST_STRING_1);
+            checkState(0, null, TEST_STRING_1, "after setting first string.");
+
+            Callback<String> supplierObserver = new Callback<String>() {
+                @Override
+                public void onResult(String result) {
+                    mCallCount++;
+                    mLastSuppliedString = result;
+                }
+            };
+
+            mSupplier.addObserver(supplierObserver);
+
+            checkState(0, null, TEST_STRING_1, "after setting observer.");
+
+            mSupplier.set(TEST_STRING_2);
+            checkState(1, TEST_STRING_2, TEST_STRING_2, "after setting second string.");
+        });
+
+        handler.post(() -> checkState(1, TEST_STRING_2, TEST_STRING_2, "in second message loop."));
+    }
+
+    @Test
+    public void testObserverNotification_RegisterObserverAfterSetThenRemove() {
+        Handler handler = new Handler();
+        handler.post(() -> {
+            mSupplier.set(TEST_STRING_1);
+            checkState(0, null, TEST_STRING_1, "after setting first string.");
+
+            Callback<String> supplierObserver = new Callback<String>() {
+                @Override
+                public void onResult(String result) {
+                    mCallCount++;
+                    mLastSuppliedString = result;
+                }
+            };
+
+            mSupplier.addObserver(supplierObserver);
+
+            checkState(0, null, TEST_STRING_1, "after setting observer.");
+
+            mSupplier.removeObserver(supplierObserver);
+        });
+
+        handler.post(() -> checkState(0, null, TEST_STRING_1, "in second message loop."));
+    }
+
+    @Test
+    public void testObserverNotification_RemoveObserverInsideCallback() {
+        Callback<String> supplierObserver = new Callback<String>() {
+            @Override
+            public void onResult(String result) {
+                mCallCount++;
+                mLastSuppliedString = result;
+                mSupplier.removeObserver(this);
+            }
+        };
+
+        mSupplier.addObserver(supplierObserver);
+        checkState(0, null, null, "before setting first string.");
+
+        mSupplier.set(TEST_STRING_1);
+        checkState(1, TEST_STRING_1, TEST_STRING_1, "after setting first string.");
+
+        mSupplier.set(TEST_STRING_2);
+        checkState(1, TEST_STRING_1, TEST_STRING_2, "after setting second string.");
+    }
+
+    private void checkState(int expectedCallCount, String expectedLastSuppliedString,
+            String expectedStringFromGet, String assertDescription) {
+        Assert.assertEquals(
+                "Incorrect call count " + assertDescription, expectedCallCount, mCallCount);
+        Assert.assertEquals("Incorrect last supplied string " + assertDescription,
+                expectedLastSuppliedString, mLastSuppliedString);
+        Assert.assertEquals(
+                "Incorrect #get() " + assertDescription, expectedStringFromGet, mSupplier.get());
+    }
+}