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 MySonarPluginTest.java. In the test method body we create our plugin which we want to test as well as a SonarConnectionMock. In this contrived example we simply assert that our plugin's connected status is what we expect.

@RunWith(RobolectricTestRunner.class)
public class MySonarPluginTest {

  @Test
  public void myTest() {
    final MySonarPlugin plugin = new MySonarPlugin();
    final SonarConnectionMock connection = new SonarConnectionMock();

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

There are two mock classes that are used to construct tests SonarConnectionMock and SonarResponderMock. 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 MySonarPlugin plugin = new MySonarPlugin();
  final SonarConnectionMock connection = new SonarConnectionMock();
  final SonarResponderMock responder = new SonarResponderMock();

  plugin.onConnect(connection);

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

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

C++

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

#include <MySonarPlugin/MySonarPlugin.h>
#include <FlipperTestLib/FlipperConnectionMock.h>
#include <FlipperTestLib/SonarResponderMock.h>

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

namespace facebook {
namespace flipper {
namespace test {

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

  MySonarPlugin 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);
}