load("@bazel_skylib//rules:diff_test.bzl", "diff_test")
load("@bazel_skylib//rules:write_file.bzl", "write_file")

write_file(
    name = "a",
    out = "a.txt",
    content = [
        "foobar",
    ],
)

write_file(
    name = "b",
    out = "b.txt",
    content = [
        "moocow",
    ],
)

write_file(
    name = "expected",
    out = "expected.txt",
    content = [
        "1c1",
        "< foobar",
        "\\ No newline at end of file",
        "---",
        "> moocow",
        "\\ No newline at end of file",
        "",
    ],
)

genrule(
    name = "patch",
    srcs = [
        ":a",
        ":b",
    ],
    outs = ["patch.patch"],
    cmd = "$(execpath //:diff) $(execpath :a) $(execpath :b) > $@ || true",
    tools = ["//:diff"],
)

diff_test(
    name = "test",
    file1 = ":expected",
    file2 = ":patch",
)