diff_test: add rule and tests (#136)
This new test rule compares two files and passes
if the files match.
On Linux/macOS/non-Windows, the test compares
files using 'diff'.
On Windows, the test compares files using
'fc.exe'. This utility is available on all Windows
versions I tried (Windows 2008 Server, Windows
2016 Datacenter Core).
See https://github.com/bazelbuild/bazel/issues/5508
See https://github.com/bazelbuild/bazel/issues/4319
diff --git a/rules/diff_test.bzl b/rules/diff_test.bzl
new file mode 100644
index 0000000..6fb3581
--- /dev/null
+++ b/rules/diff_test.bzl
@@ -0,0 +1,145 @@
+# Copyright 2019 The Bazel 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.
+
+"""A test rule that compares two binary files.
+
+The rule uses a Bash command (diff) on Linux/macOS/non-Windows, and a cmd.exe
+command (fc.exe) on Windows (no Bash is required).
+"""
+
+def _runfiles_path(f):
+ if f.root.path:
+ return f.path[len(f.root.path) + 1:] # generated file
+ else:
+ return f.path # source file
+
+def _diff_test_impl(ctx):
+ if ctx.attr.is_windows:
+ test_bin = ctx.actions.declare_file(ctx.label.name + "-test.bat")
+ ctx.actions.write(
+ output = test_bin,
+ content = r"""@echo off
+SETLOCAL ENABLEEXTENSIONS
+SETLOCAL ENABLEDELAYEDEXPANSION
+set MF=%RUNFILES_MANIFEST_FILE:/=\%
+set PATH=%SYSTEMROOT%\system32
+set F1={file1}
+set F2={file2}
+if "!F1:~0,9!" equ "external/" (set F1=!F1:~9!) else (set F1=!TEST_WORKSPACE!/!F1!)
+if "!F2:~0,9!" equ "external/" (set F2=!F2:~9!) else (set F2=!TEST_WORKSPACE!/!F2!)
+for /F "tokens=2* usebackq" %%i in (`findstr.exe /l /c:"!F1! " "%MF%"`) do (
+ set RF1=%%i
+ set RF1=!RF1:/=\!
+)
+if "!RF1!" equ "" (
+ echo>&2 ERROR: !F1! not found
+ exit /b 1
+)
+for /F "tokens=2* usebackq" %%i in (`findstr.exe /l /c:"!F2! " "%MF%"`) do (
+ set RF2=%%i
+ set RF2=!RF2:/=\!
+)
+if "!RF2!" equ "" (
+ echo>&2 ERROR: !F2! not found
+ exit /b 1
+)
+fc.exe 2>NUL 1>NUL /B "!RF1!" "!RF2!"
+if %ERRORLEVEL% neq 0 (
+ if %ERRORLEVEL% equ 1 (
+ echo>&2 FAIL: files "{file1}" and "{file2}" differ
+ exit /b 1
+ ) else (
+ fc.exe /B "!RF1!" "!RF2!"
+ exit /b %errorlevel%
+ )
+)
+""".format(
+ file1 = _runfiles_path(ctx.file.file1),
+ file2 = _runfiles_path(ctx.file.file2),
+ ),
+ is_executable = True,
+ )
+ else:
+ test_bin = ctx.actions.declare_file(ctx.label.name + "-test.sh")
+ ctx.actions.write(
+ output = test_bin,
+ content = r"""#!/bin/bash
+set -euo pipefail
+F1="{file1}"
+F2="{file2}"
+[[ "$F1" =~ external/* ]] && F1="${{F1#external/}}" || F1="$TEST_WORKSPACE/$F1"
+[[ "$F2" =~ external/* ]] && F2="${{F2#external/}}" || F2="$TEST_WORKSPACE/$F2"
+if [[ -d "${{RUNFILES_DIR:-/dev/null}}" && "${{RUNFILES_MANIFEST_ONLY:-}}" != 1 ]]; then
+ RF1="$RUNFILES_DIR/$F1"
+ RF2="$RUNFILES_DIR/$F2"
+elif [[ -f "${{RUNFILES_MANIFEST_FILE:-/dev/null}}" ]]; then
+ RF1="$(grep -F -m1 "$F1 " "$RUNFILES_MANIFEST_FILE" | sed 's/^[^ ]* //')"
+ RF2="$(grep -F -m1 "$F2 " "$RUNFILES_MANIFEST_FILE" | sed 's/^[^ ]* //')"
+else
+ echo >&2 "ERROR: could not find \"{file1}\" and \"{file2}\""
+ exit 1
+fi
+if ! diff "$RF1" "$RF2"; then
+ echo >&2 "FAIL: files \"{file1}\" and \"{file2}\" differ"
+ exit 1
+fi
+""".format(
+ file1 = _runfiles_path(ctx.file.file1),
+ file2 = _runfiles_path(ctx.file.file2),
+ ),
+ is_executable = True,
+ )
+ return DefaultInfo(
+ executable = test_bin,
+ files = depset(direct = [test_bin]),
+ runfiles = ctx.runfiles(files = [test_bin, ctx.file.file1, ctx.file.file2]),
+ )
+
+_diff_test = rule(
+ attrs = {
+ "file1": attr.label(
+ allow_single_file = True,
+ mandatory = True,
+ ),
+ "file2": attr.label(
+ allow_single_file = True,
+ mandatory = True,
+ ),
+ "is_windows": attr.bool(mandatory = True),
+ },
+ test = True,
+ implementation = _diff_test_impl,
+)
+
+def diff_test(name, file1, file2, **kwargs):
+ """A test that compares two files.
+
+ The test succeeds if the files' contents match.
+
+ Args:
+ name: The name of the test rule.
+ file1: Label of the file to compare to <code>file2</code>.
+ file2: Label of the file to compare to <code>file1</code>.
+ **kwargs: The <a href="https://docs.bazel.build/versions/master/be/common-definitions.html#common-attributes-tests">common attributes for tests</a>.
+ """
+ _diff_test(
+ name = name,
+ file1 = file1,
+ file2 = file2,
+ is_windows = select({
+ "@bazel_tools//src/conditions:host_windows": True,
+ "//conditions:default": False,
+ }),
+ **kwargs
+ )
