bazel-lib/lib/tests/write_source_files/write_source_file_test.bzl

"""Tests for write_source_files"""
# Inspired by https://github.com/cgrindel/bazel-starlib/blob/main/updatesrc/private/updatesrc_update_test.bzl

load("//lib/private:write_source_file.bzl", _write_source_file = "write_source_file")
load("//lib/private:directory_path.bzl", "DirectoryPathInfo")

def _write_source_file_test_impl_sh(ctx, in_file_path, out_file_path):
    test = ctx.actions.declare_file(
        ctx.label.name + "_test.sh",
    )

    contents = []

    contents.append("""
#!/usr/bin/env bash
set -o errexit -o nounset -o pipefail

assert_different() {
  local in_file="${1}"
  local out_file="${2}"
  diff  "${in_file}" "${out_file}" > /dev/null && (echo >&2 "Expected files to differ. in: ${in_file}, out: ${out_file}" && return -1)
  return 0
}

assert_same() {
  local in_file="${1}"
  local out_file="${2}"
  diff  "${in_file}" "${out_file}" || (echo >&2 "Expected files to be same. in: ${in_file}, out: ${out_file}" && return -1)
}""")

    contents.append("""
# Check that in and out files are different
assert_different {in_file} {out_file}
""".format(
        in_file = in_file_path,
        out_file = out_file_path,
    ))

    contents.append("""# Write to the source files
{write_source_files}
""".format(write_source_files = ctx.file.write_source_file_target.short_path))

    contents.append("""# Check that in and out files are the same
assert_same {in_file} {out_file}""".format(
        in_file = in_file_path,
        out_file = out_file_path,
    ))

    ctx.actions.write(
        output = test,
        is_executable = True,
        content = "\n".join(contents),
    )

    return test

def _write_source_file_test_impl_bat(ctx, in_file_path, out_file_path):
    test = ctx.actions.declare_file(
        ctx.label.name + "_test.bat",
    )

    # BUG: Windows is having trouble executing the symlink to the write_source_files executable,
    # but it is able to execute the actual output script so point to that for now.
    #
    # What we would use if this bug didn't exist:
    #    write_source_files = ctx.executable.write_source_file_target.short_path.replace("/", "\\")
    #
    # Instead back out of the runfiles execution directory:
    #    write_to_source_files_test_test.bat.runfiles/aspect_bazel_lib
    # And point to the output script.
    write_source_files = "..\\..\\%s" % ctx.executable.write_source_file_target.basename

    contents = []

    contents.append("""
@rem @generated by @aspect_bazel_lib//:lib/tests/write_source_files:write_source_file_test.bzl
@echo off
@rem Check that in and out files are different
call :assert_different {in_file}, {out_file}
if %errorlevel% neq 0 exit /b 1
""".format(
        in_file = in_file_path.replace("/", "\\"),
        out_file = out_file_path.replace("/", "\\"),
    ))

    contents.append("""
@rem Write to the source files
call {write_source_files}
if %errorlevel% neq 0 exit /b 1
""".format(write_source_files = write_source_files))

    contents.append("""
@rem Check that in and out files are the same
call :assert_same {in_file}, {out_file}
if %errorlevel% neq 0 exit /b 1
""".format(
        in_file = in_file_path.replace("/", "\\"),
        out_file = out_file_path.replace("/", "\\"),
    ))

    contents.append("""
exit /b 0

:assert_different
fc /b %~1 %~2 > nul
if %errorlevel% equ 1 exit /b 0
echo Error: %~1 and %~2 are not different
exit /b 1

:assert_same
fc /b %~1 %~2 > nul
if %errorlevel% equ 0 exit /b 0
echo Error: %~1 and %~2 are not the same
exit /b 1
""")

    ctx.actions.write(
        output = test,
        is_executable = True,
        content = "\n".join(contents).replace("\n", "\r\n"),
    )

    return test

def _write_source_file_test_impl(ctx):
    is_windows = ctx.target_platform_has_constraint(ctx.attr._windows_constraint[platform_common.ConstraintValueInfo])

    if DirectoryPathInfo in ctx.attr.in_file:
        in_file = ctx.attr.in_file[DirectoryPathInfo].directory
        in_file_path = "/".join([in_file.short_path, ctx.attr.in_file[DirectoryPathInfo].path])
    else:
        if len(ctx.files.in_file) != 1:
            fail("in_file must be a single file or a target that provides a DirectoryPathInfo")
        in_file = ctx.files.in_file[0]
        in_file_path = in_file.short_path

    if is_windows:
        test = _write_source_file_test_impl_bat(ctx, in_file_path, ctx.file.out_file.short_path)
    else:
        test = _write_source_file_test_impl_sh(ctx, in_file_path, ctx.file.out_file.short_path)

    return DefaultInfo(
        executable = test,
        runfiles = ctx.runfiles(
            files = [ctx.executable.write_source_file_target, in_file, ctx.file.out_file],
        ),
    )

_write_source_file_test = rule(
    implementation = _write_source_file_test_impl,
    attrs = {
        "write_source_file_target": attr.label(
            allow_single_file = True,
            executable = True,
            # Intentionally use the target platform since the target is always meant to be `bazel
            # run` on the host machine but we don't want to transition it to the host platform and
            # have the generated file rebuilt in a separate output tree. Target platform should
            # always be equal to the host platform when using `write_source_files`.
            cfg = "target",
            mandatory = True,
        ),
        "out_file": attr.label(
            allow_single_file = True,
            mandatory = True,
        ),
        "in_file": attr.label(
            allow_files = True,
            mandatory = True,
        ),
        "_windows_constraint": attr.label(default = "@platforms//os:windows"),
    },
    test = True,
)

def write_source_file_test(name, in_file, out_file):
    """Stamp a write_source_files executable and a test to run against it"""

    _write_source_file(
        name = name + "_updater",
        in_file = in_file,
        out_file = out_file,
        diff_test = False,
    )

    # Note that for testing we update the source files in the sandbox,
    # not the actual source tree.
    _write_source_file_test(
        name = name,
        write_source_file_target = name + "_updater",
        in_file = in_file,
        out_file = out_file,
        timeout = "short",
    )