1 files changed, 122 insertions, 0 deletions
diff --git a/go/private/tools/files_equal_test.bzl b/go/private/tools/files_equal_test.bzl
new file mode 100644
index 00000000..90377bf3
--- /dev/null
+++ b/go/private/tools/files_equal_test.bzl
@@ -0,0 +1,122 @@
+# Copyright 2016 The Bazel Go Rules Authors. All rights reserved.
+# Copyright 2016 The Closure Rules Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Tests that two files contain the same data."""
+
+def files_equal_test(name, golden, actual, error_message = None, **kwargs):
+    # This genrule creates a Bash script: the source of the actual test.
+    # The script:
+    #   1. Initializes the Bash runfiles library (see
+    #      @bazel_tools//tools/bash/runfiles/runfiles.bash).
+    #   2. Stores command line arguments into variables.
+    #   3. Computes runfile paths for the GOLDEN and ACTUAL files.
+    #   4. Calls "rlocation" from runfiles.bash to locates the runfiles.
+    #   5. Computes and compares checksums.
+    native.genrule(
+        name = name + "_src",
+        outs = [name + "-src.sh"],
+        executable = True,
+        visibility = ["//visibility:private"],
+        cmd = r"""cat >$@ <<'eof'
+#!/usr/bin/env bash
+# sh_test() source, generated by @io_bazel_rules_go//go/private/tools/files_equal_test.bzl
+
+### 1. initialize the Bash runfiles library
+
+# --- begin runfiles.bash initialization ---
+# 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 " \
+            "$$RUNFILES_MANIFEST_FILE" | cut -d ' ' -f 2-)"
+else
+  echo >&2 "ERROR: cannot find @bazel_tools//tools/bash/runfiles:runfiles.bash"
+  exit 1
+fi
+# --- end runfiles.bash initialization ---
+
+### 2. Store command line arguments into variables.
+
+declare -r GOLDEN="$${1}"
+declare -r ACTUAL="$${2}"
+declare -r ERROR_MSG="$${3:-FILES DO NOT HAVE EQUAL CONTENTS}"
+
+### 3. Compute runfile paths.
+
+# Strip "external/" prefix OR prepend workspace name and strip "./" prefix.
+[[ "$$GOLDEN" =~ external/* ]] && F1="$${GOLDEN#external/}" || F1="$$TEST_WORKSPACE/$${GOLDEN#./}"
+[[ "$$ACTUAL" =~ external/* ]] && F2="$${ACTUAL#external/}" || F2="$$TEST_WORKSPACE/$${ACTUAL#./}"
+
+### 4. Locate the runfiles.
+
+F1="$$(rlocation "$$F1")"
+F2="$$(rlocation "$$F2")"
+
+if [[ "$$F1" == "$$F2" ]]; then
+  echo >&2 "GOLDEN and ACTUAL should be different files"
+  exit 1
+fi
+
+### 5. Compute and compare checksums.
+
+function checksum() {
+  if command -v openssl >/dev/null; then
+    openssl sha1 $$1 | cut -f 2 -d ' '
+  elif command -v sha256sum >/dev/null; then
+    sha256sum $$1 | cut -f 1 -d ' '
+  elif command -v shasum >/dev/null; then
+    cat $$1 | shasum -a 256 | cut -f 1 -d ' '
+  else
+    echo please install openssl >&2
+    exit 1
+  fi
+}
+SUM1=$$(checksum "$$F1")
+SUM2=$$(checksum "$$F2")
+if [[ $${SUM1} != $${SUM2} ]]; then
+  echo "ERROR: $$ERROR_MSG" >&2
+  echo "$$GOLDEN $${SUM1}" >&2
+  echo "$$ACTUAL $${SUM2}" >&2
+  exit 1
+fi
+eof""",
+    )
+
+    native.sh_test(
+        name = name,
+        srcs = [name + "-src.sh"],
+        data = [
+            "@bazel_tools//tools/bash/runfiles",
+            actual,
+            golden,
+        ],
+        args = [
+            "$(location %s)" % golden,
+            "$(location %s)" % actual,
+            error_message,
+        ],
+        **kwargs
+    )