Windows: tests now work with native test wrapper (#263)

Windows: tests now work with native test wrapper

See https://github.com/bazelbuild/bazel/issues/6622

examples/cmake_hello_world_lib/static/BUILD

@@ -89,8 +89,9 @@ cc_binary(
 sh_test(
     name = "test_hello",
     srcs = ["test_hello.sh"],
-    args = ["libhello_example"],
+    args = ["$(location libhello_example)"],
     data = [":libhello_example"],
+    deps = ["@bazel_tools//tools/bash/runfiles"],
     tags = ["windows"],
     visibility = ["//:__pkg__"],
 )
@@ -98,8 +99,9 @@ sh_test(
 sh_test(
     name = "test_hello_ninja",
     srcs = ["test_hello.sh"],
-    args = ["libhello_example_ninja"],
+    args = ["$(location libhello_example_ninja)"],
     data = [":libhello_example_ninja"],
+    deps = ["@bazel_tools//tools/bash/runfiles"],
     tags = ["windows"],
     visibility = ["//:__pkg__"],
 )
@@ -107,8 +109,9 @@ sh_test(
 sh_test(
     name = "test_hello_nmake",
     srcs = ["test_hello.sh"],
-    args = ["libhello_example_nmake"],
+    args = ["$(location libhello_example_nmake)"],
     data = [":libhello_example_nmake"],
+    deps = ["@bazel_tools//tools/bash/runfiles"],
     tags = ["windows"],
     visibility = ["//:__pkg__"],
 )

examples/cmake_hello_world_lib/static/test_hello.sh

@@ -1,3 +1,29 @@
 #!/usr/bin/env bash
 
-$(rlocation rules_foreign_cc/examples/cmake_hello_world_lib/$1)
+# --- begin runfiles.bash initialization ---
+# The runfiles library itself defines rlocation which you would need to look
+# up the library's runtime location, thus we have a chicken-and-egg problem.
+#
+# Copy-pasted from Bazel's Bash runfiles library (tools/bash/runfiles/runfiles.bash).
+set -euo pipefail
+if [[ ! -d "${RUNFILES_DIR:-/dev/null}" && ! -f "${RUNFILES_MANIFEST_FILE:-/dev/null}" ]]; then
+  if [[ -f "$0.runfiles_manifest" ]]; then
+    export RUNFILES_MANIFEST_FILE="$0.runfiles_manifest"
+  elif [[ -f "$0.runfiles/MANIFEST" ]]; then
+    export RUNFILES_MANIFEST_FILE="$0.runfiles/MANIFEST"
+  elif [[ -f "$0.runfiles/bazel_tools/tools/bash/runfiles/runfiles.bash" ]]; then
+    export RUNFILES_DIR="$0.runfiles"
+  fi
+fi
+if [[ -f "${RUNFILES_DIR:-/dev/null}/bazel_tools/tools/bash/runfiles/runfiles.bash" ]]; then
+  source "${RUNFILES_DIR}/bazel_tools/tools/bash/runfiles/runfiles.bash"
+elif [[ -f "${RUNFILES_MANIFEST_FILE:-/dev/null}" ]]; then
+  source "$(grep -m1 "^bazel_tools/tools/bash/runfiles/runfiles.bash " \
+            "$RUNFILES_MANIFEST_FILE" | cut -d ' ' -f 2-)"
+else
+  echo >&2 "ERROR: cannot find @bazel_tools//tools/bash/runfiles:runfiles.bash"
+  exit 1
+fi
+# --- end runfiles.bash initialization ---
+
+$(rlocation $TEST_WORKSPACE/$1)

test/standard_cxx_flags_test/tests.bzl

@@ -19,12 +19,17 @@ def _impl(ctx):
     if "-fblah3" in flags.cxx_linker_static:
         fail("Static linker flags should not contain '-fblah3'")
 
-    # to satisfy test rule requirement to be executable
+    exe = ctx.outputs.out
     ctx.actions.write(
-        output = ctx.outputs.executable,
-        content = "",
+        output = exe,
+        is_executable = True,
+        # The file must not be empty because running an empty .bat file as a
+        # subprocess fails on Windows, so we write one space to it.
+        content = " ",
     )
 
+    return [DefaultInfo(files = depset([exe]), executable = exe)]
+
 def assert_contains_once(arr, value):
     cnt = 0
     for elem in arr:
@@ -35,12 +40,23 @@ def assert_contains_once(arr, value):
     if cnt > 1:
         fail("Value is included multiple times: " + value)
 
-flags_test = rule(
+_flags_test = rule(
     implementation = _impl,
     attrs = {
         "_cc_toolchain": attr.label(default = Label("@bazel_tools//tools/cpp:current_cc_toolchain")),
+        "out": attr.output(),
     },
     toolchains = ["@bazel_tools//tools/cpp:toolchain_type"],
     fragments = ["cpp"],
     test = True,
 )
+
+def flags_test(name, **kwargs):
+    _flags_test(
+        name = name,
+        # On Windows we need the ".bat" extension.
+        # On other platforms the extension doesn't matter.
+        # Therefore we can use ".bat" on every platform.
+        out = name + ".bat",
+        **kwargs
+    )