Use --test-root to pass files to Bazel tests.

The current implementation makes tests fail when it is imported from a
different Bazel workspace. We fix that by using
the --test-root flag to pass the rootpath to the
tests.

Author: RafaelMarinheiro

BUILD.bazel

@@ -51,7 +51,10 @@ py_binary(
 
 genrule(
     name = "gen_build_info_h",
-    srcs = ["CHANGES.md", "build_info.h.tmpl"],
+    srcs = [
+        "CHANGES.md",
+        "build_info.h.tmpl",
+    ],
     outs = ["glslang/build_info.h"],
     cmd = "$(location build_info) $$(dirname $(location CHANGES.md)) -i $(location build_info.h.tmpl) -o $(location glslang/build_info.h)",
     tools = [":build_info"],
@@ -92,10 +95,8 @@ cc_library(
     ) + [
         "OGLCompilersDLL/InitializeDll.cpp",
     ] + select({
-        "@bazel_tools//src/conditions:windows":
-            ["glslang/OSDependent/Windows/ossource.cpp"],
-        "//conditions:default":
-            ["glslang/OSDependent/Unix/ossource.cpp"],
+        "@bazel_tools//src/conditions:windows": ["glslang/OSDependent/Windows/ossource.cpp"],
+        "//conditions:default": ["glslang/OSDependent/Unix/ossource.cpp"],
     }),
     hdrs = glob([
         "glslang/HLSL/*.h",
@@ -118,7 +119,10 @@ cc_library(
     ],
     linkopts = select({
         "@bazel_tools//src/conditions:windows": [""],
-        "//conditions:default": ["-lm", "-lpthread"],
+        "//conditions:default": [
+            "-lm",
+            "-lpthread",
+        ],
     }),
     linkstatic = 1,
 )
@@ -224,18 +228,6 @@ cc_binary(
     ],
 )
 
-filegroup(
-    name = "test_files",
-    srcs = glob(
-        ["Test/**"],
-        exclude = [
-            "Test/bump",
-            "Test/glslangValidator",
-            "Test/runtests",
-        ],
-    ),
-)
-
 cc_library(
     name = "glslang_test_lib",
     testonly = 1,
@@ -249,16 +241,9 @@ cc_library(
         "gtests/main.cpp",
     ],
     copts = COMMON_COPTS,
-    data = [":test_files"],
-    defines = select({
-        # Unfortunately we can't use $(location) in cc_library at the moment.
-        # See https://github.com/bazelbuild/bazel/issues/1023
-        # So we'll specify the path manually.
-        "@bazel_tools//src/conditions:windows":
-            ["GLSLANG_TEST_DIRECTORY='\"../../../../../Test\"'"],
-        "//conditions:default":
-            ["GLSLANG_TEST_DIRECTORY='\"Test\"'"],
-    }),
+    defines = [
+        "GLSLANG_TEST_DIRECTORY='\"USE_FLAG_INSTEAD\"'",
+    ],
     linkstatic = 1,
     deps = [
         ":SPIRV",
@@ -281,9 +266,13 @@ GLSLANG_TESTS = glob(
 [cc_test(
     name = test_file.replace("gtests/", "").replace(".FromFile.cpp", "") + "_test",
     srcs = [test_file],
+    args = [
+        "--test-root",
+        "$(rootpath Test)",
+    ],
     copts = COMMON_COPTS,
     data = [
-        ":test_files",
+        "Test",
     ],
     deps = [
         ":SPIRV",