如何通过Bazel从JUnit测试执行中找到Java源代码文件的路径

Question

我想通过JUnit测试来检查monoreo代码库中的一个文本文件。JUnit测试通过bazel test命令执行。如何配置Bazel将源代码目录路径(不是缓存的编译JAR文件路径(传递给我的单元测试？它可能是CLI参数、环境变量等。

Answer 1

实现这一点的一种方法是使用data属性，该属性使文件在运行时可用于测试(和其他二进制文件(，对于Java，Bazel提供了Runfiles库，用于查找数据文件。例如：

BUILD:

java_test(
name = "TextFileTest",
srcs = ["javatests/txtfile/TextFileTest.java"],
data = ["text.txt"],
deps = [
"@bazel_tools//tools/java/runfiles:runfiles",
"@maven//:junit_junit",
],
)

WORKSPACE:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
RULES_JVM_EXTERNAL_TAG = "4.2"
RULES_JVM_EXTERNAL_SHA = "cd1a77b7b02e8e008439ca76fd34f5b07aecb8c752961f9640dea15e9e5ba1ca"
http_archive(
name = "rules_jvm_external",
strip_prefix = "rules_jvm_external-%s" % RULES_JVM_EXTERNAL_TAG,
sha256 = RULES_JVM_EXTERNAL_SHA,
url = "https://github.com/bazelbuild/rules_jvm_external/archive/%s.zip" % RULES_JVM_EXTERNAL_TAG,
)
load("@rules_jvm_external//:defs.bzl", "maven_install")
maven_install(
artifacts = [
"junit:junit:4.13.2",
],
repositories = [
"https://repo1.maven.org/maven2",
],
)

javatests/txtfile/TextFileTest.java:

package txtfile;
import com.google.devtools.build.runfiles.Runfiles;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.Path;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
@RunWith(JUnit4.class)
public class TextFileTest {
@Test
public void testTextFile() throws Exception {
Runfiles runfiles = Runfiles.create();
Path path = Paths.get(runfiles.rlocation("__main__/text.txt"));
String line = Files.readAllLines(path).get(0);
Assert.assertEquals(line, "this is text");
}
}

text.txt:

this is text

$ bazel test TextFileTest
INFO: Build option --test_sharding_strategy has changed, discarding analysis cache.
INFO: Analyzed target //:TextFileTest (0 packages loaded, 547 targets configured).
INFO: Found 1 test target...
Target //:TextFileTest up-to-date:
bazel-bin/TextFileTest.jar
bazel-bin/TextFileTest
INFO: Elapsed time: 0.288s, Critical Path: 0.01s
INFO: 1 process: 1 internal.
INFO: Build completed successfully, 1 total action
//:TextFileTest                                                 (cached) PASSED in 0.3s
Executed 0 out of 1 test: 1 test passes.
INFO: Build completed successfully, 1 total action

请注意，在runfiles.rlocation("__main__/text.txt")中，__main__是工作区名称，默认情况下为__main__。如果WORKSPACE文件中有一个workspace(name = "workspace name")，那么工作区名称将根据该名称进行设置。