how to write extended rule for java test in Bazel? - bazel

Question

What I figured currently is creating a AllTest and run it with junit. But, I am not satisfied with it. I want this rule can create as many tests as many java test file in created in codebase.
def junit_suite_test(name, srcs, deps, size="small", resources=[], classpath_resources=[], jvm_flags=[], tags=[], data=[]):
tests = []
package = PACKAGE_NAME.replace("src/test/java/", "").replace("/", ".")
for src in srcs:
if src.endswith("Test.java"):
if "/" in src:
src = package + "." + src.replace("/", ".")
tests += [src.replace(".java", ".class")]
native.genrule(
name = name + "-AllTests-gen",
outs = ["AllTests.java"],
cmd = """
cat <<EOF >> $#
package %s;
import org.junit.runner.RunWith;
import org.junit.runners.Suite;
#RunWith(Suite.class)
#Suite.SuiteClasses({%s})
public class AllTests {}
EOF
""" % (package, ",".join(tests))
)
native.java_test(
name = name,
srcs = srcs + ["AllTests.java"],
test_class = package + ".AllTests",
resources = resources,
classpath_resources = classpath_resources,
data = data,
size = size,
tags = tags,
jvm_flags = jvm_flags,
deps = deps + [
],
)

Answer 1

Hi you can do something like that:
[java_test(name = s[:-5], srcs = s) for s in glob(["*.java"])]
That will create on test target per java file.
With that method, your macro would looks like:
def junit_suite_test(name, srcs, deps, size="small", resources=[], classpath_resources=[], jvm_flags=[], tags=[], data=[]):
[native.java_test(
name = name,
srcs = src,
resources = resources,
classpath_resources = classpath_resources,
data = data,
size = size,
tags = tags,
jvm_flags = jvm_flags,
deps = deps,
) for src in srcs if src.endswith("Test.java")]
Of course you probably needs some adaptation to feed in the good sources.
However, I would recommend against doing that over your solution as too much parallelisms can actually be slower in fine. The test log and the XML file will report the actual failing test case and you can use shard_count to increase parallelism is really needed.