flipper/docs/testing.md

id, title, sidebar_label

id	title	sidebar_label
testing	Testing	Testing

Developer tools are only used if they work. We have built APIs to test plugins.

Android

Start by creating your first test file in this directory MyFlipperPluginTest.java. In the test method body we create our plugin which we want to test as well as a FlipperConnectionMock. In this contrived example we simply assert that our plugin's connected status is what we expect.

@RunWith(RobolectricTestRunner.class)
public class MyFlipperPluginTest {

  @Test
  public void myTest() {
    final MyFlipperPlugin plugin = new MyFlipperPlugin();
    final FlipperConnectionMock connection = new FlipperConnectionMock();

    plugin.onConnect(connection);
    assertThat(plugin.connected(), equalTo(true));
  }
}

There are two mock classes that are used to construct tests FlipperConnectionMock and FlipperResponderMock. Together these can be used to write very powerful tests to verify the end to end behavior of your plugin. For example we can test if for a given incoming message our plugin responds as we expect.

@Test
public void myTest() {
  final MyFlipperPlugin plugin = new MyFlipperPlugin();
  final FlipperConnectionMock connection = new FlipperConnectionMock();
  final FlipperResponderMock responder = new FlipperResponderMock();

  plugin.onConnect(connection);

  final FlipperObject params = new FlipperObject.Builder()
      .put("phrase", "flipper")
      .build();
  connection.receivers.get("myMethod").onReceive(params, responder);

  assertThat(responder.successes, hasItem(
      new FlipperObject.Builder()
          .put("phrase", "ranos")
          .build()));
}

C++

Start by creating your first test file in this directory MyFlipperPluginTests.cpp and import the testing utilities from xplat//sonar/xplat:FlipperTestLib. These utilities mock out core pieces of the communication channel so that you can test your plugin in isolation.

#include <MyFlipperPlugin/MyFlipperPlugin.h>
#include <FlipperTestLib/FlipperConnectionMock.h>
#include <FlipperTestLib/FlipperResponderMock.h>

#include <folly/json.h>
#include <gtest/gtest.h>

namespace facebook {
namespace flipper {
namespace test {

TEST(MyFlipperPluginTests, testDummy) {
  EXPECT_EQ(1 + 1, 2);
}

} // namespace test
} // namespace flipper
} // namespace facebook

Here is a simple test using these mock utilities to create a plugin, send some data, and assert that the result is as expected.

TEST(MyFlipperPluginTests, testDummy) {
  std::vector<folly::dynamic> successfulResponses;
  auto responder = std::make_unique<FlipperResponderMock>(&successfulResponses);
  auto conn = std::make_shared<FlipperConnectionMock>();

  MyFlipperPlugin plugin;
  plugin.didConnect(conn);

  folly::dynamic message = folly::dynamic::object("param1", "hello");
  folly::dynamic expectedResponse = folly::dynamic::object("response", "Hi there");

  auto receiver = conn->receivers_["someMethod"];
  receiver(message, std::move(responder));

  EXPECT_EQ(successfulResponses.size(), 1);
  EXPECT_EQ(successfulResponses.back(), expectedResponse);
}