Fix test

Summary: Add an ability to inspect errors reported through `ErrorReportingRunnable`.

Reviewed By: jknoxville

Differential Revision: D14640270

fbshipit-source-id: a5a79d647e20d5d46c85aac2a814c77abbc624b7

android/src/main/java/com/facebook/flipper/testing/FlipperConnectionMock.java

@@ -19,6 +19,7 @@ import java.util.Map;
 public class FlipperConnectionMock implements FlipperConnection {
   public final Map<String, FlipperReceiver> receivers = new HashMap<>();
   public final Map<String, List<Object>> sent = new HashMap<>();
+  public final List<Throwable> errors = new ArrayList<>();
 
   @Override
   public void send(String method, FlipperObject params) {
@@ -47,7 +48,9 @@ public class FlipperConnectionMock implements FlipperConnection {
   }
 
   @Override
-  public void reportError(Throwable throwable) {}
+  public void reportError(Throwable throwable) {
+    errors.add(throwable);
+  }
 
   @Override
   public void receive(String method, FlipperReceiver receiver) {

android/src/test/java/com/facebook/flipper/plugins/inspector/InspectorFlipperPluginTest.java

@@ -7,6 +7,7 @@
  */
 package com.facebook.flipper.plugins.inspector;
 
+import static com.facebook.flipper.plugins.inspector.ThrowableMessageMatcher.hasThrowableWithMessage;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.hasItem;
 import static org.hamcrest.MatcherAssert.assertThat;
@@ -31,8 +32,8 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import javax.annotation.Nullable;
+import org.hamcrest.CoreMatchers;
 import org.junit.Before;
-import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.Mockito;
@@ -297,8 +298,7 @@ public class InspectorFlipperPluginTest {
     Mockito.verify(decorView, Mockito.times(1)).removeView(Mockito.any(TouchOverlayView.class));
   }
 
-  @Ignore("Will be resurrected with next diff in stack")
-  @Test(expected = RuntimeException.class)
+  @Test
   public void testNullChildThrows() throws Exception {
     final InspectorFlipperPlugin plugin =
         new InspectorFlipperPlugin(mApp, mDescriptorMapping, mScriptingEnvironment, null);
@@ -309,7 +309,7 @@ public class InspectorFlipperPluginTest {
     final TestNode root = new TestNode();
     root.id = "test";
     root.name = "test";
-    root.children = new ArrayList<>();
+    root.children = new ArrayList<>(1);
     root.children.add(null);
     mApplicationDescriptor.root = root;
 
@@ -317,6 +317,9 @@ public class InspectorFlipperPluginTest {
     plugin.mGetNodes.onReceive(
         new FlipperObject.Builder().put("ids", new FlipperArray.Builder().put("test")).build(),
         responder);
+
+    assertThat(
+        connection.errors, CoreMatchers.hasItem(hasThrowableWithMessage("Unexpected null value")));
   }
 
   private class TestNode {

android/src/test/java/com/facebook/flipper/plugins/inspector/ThrowableMessageMatcher.java

@@ -0,0 +1,27 @@
+package com.facebook.flipper.plugins.inspector;
+
+import org.hamcrest.Description;
+import org.hamcrest.TypeSafeMatcher;
+
+/** Match a throwable with a given message. */
+class ThrowableMessageMatcher extends TypeSafeMatcher<Throwable> {
+  private final String mMessage;
+
+  public static ThrowableMessageMatcher hasThrowableWithMessage(String message) {
+    return new ThrowableMessageMatcher(message);
+  }
+
+  ThrowableMessageMatcher(String message) {
+    mMessage = message;
+  }
+
+  @Override
+  public void describeTo(Description description) {
+    description.appendText("a throwable with message ").appendText(mMessage);
+  }
+
+  @Override
+  protected boolean matchesSafely(Throwable item) {
+    return item.getMessage().equals(mMessage);
+  }
+}