为什么在 java_test 规则上运行 bazel 测试时 Bazel 找不到我的测试 class？

Question

I have a test class defined in src/handlers/MyHttpHandlerTest.java (sorry, I know it's best practice to put tests in a tests directory).

Here is my src/handlers/BUILD file:

java_test(
    name = "MyHttpHandlerTest",
    srcs = [
        "MyHttpHandler.java",
        "MyHttpHandlerTest.java",
    ],
    deps = [
        "//:java_test_deps",
        "//src/messages",
    ],
)

My test class is defined in src/handlers/MyHttpHandlerTest.java as follows (It currently doesn't assert anything -- I'm just trying to test out my installation of junit and Mockito):

package src.handlers;

import com.sun.net.httpserver.HttpExchange;
import src.messages.Message;

import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.Mockito.when;

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;

import java.io.IOException;

@ExtendWith(MockitoExtension.class)
public class MyHttpHandlerTest {

    @Mock
    Message message;

    @Mock
    HttpExchange exchange;

    @Test
    public void testGetMessage() throws IOException {
        MyHttpHandler handler = new MyHttpHandler();
        when(message.getMessage()).thenReturn("Hello world!");
        handler.setMessage(message);
        handler.handle(exchange);
    }
}

When I run bazel test //src/handlers:MyHttpHandlerTest , it successfully compiles the source files, but then returns the error:

Class not found: [handlers.MyHttpHandlerTest]

Why can't bazel find this class?

Answer 1

Bazel guesses that the the root of the Java package hierarchy is the src folder and therefore tries to load handlers.MyHttpHandlerTest . So, either change the package to actually be handlers or override Bazel's heuristic with the test_class attribute:

java_test(
    name = "MyHttpHandlerTest",
    srcs = [
        "MyHttpHandler.java",
        "MyHttpHandlerTest.java",
    ],
    deps = [
        "//:java_test_deps",
        "//src/messages",
    ],
    test_class = "src.handlers.MyHttpHandlerTest",
)