Re: [PATCH v4 4/4] t0060: verify that basename() and dirname() work as expected

> Unfortunately, some libgen implementations yield outcomes different
> from what Git expects. For example, mingw-w64-crt provides a basename()
> function, that shortens `path0/` to `path`!
> 
> So let's verify that the basename() and dirname() functions we use
> conform to what Git expects.
> 
> Derived-from-code-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>  t/t0060-path-utils.sh |   3 +
>  test-path-utils.c     | 166 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 169 insertions(+)
> 
> diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
> index 627ef85..f0152a7 100755
> --- a/t/t0060-path-utils.sh
> +++ b/t/t0060-path-utils.sh
> @@ -59,6 +59,9 @@ case $(uname -s) in
>  	;;
>  esac
>  
> +test_expect_success basename 'test-path-utils basename'
> +test_expect_success dirname 'test-path-utils dirname'
> +
>  norm_path "" ""
>  norm_path . ""
>  norm_path ./ ""
> diff --git a/test-path-utils.c b/test-path-utils.c
> index c67bf65..4ab68ac 100644
> --- a/test-path-utils.c
> +++ b/test-path-utils.c
> @@ -39,6 +39,166 @@ static void normalize_argv_string(const char **var, const char *input)
>  		die("Bad value: %s\n", input);
>  }
>  
> +struct test_data {
> +	const char *from;  /* input:  transform from this ... */
> +	const char *to;    /* output: ... to this.            */
> +};
> +
> +static int test_function(struct test_data *data, char *(*func)(char *input),
> +	const char *funcname)
> +{
> +	int failed = 0, i;
> +	char buffer[1024];
> +	char *to;
> +
> +	for (i = 0; data[i].to; i++) {
> +		if (!data[i].from)
> +			to = func(NULL);
> +		else {
> +			strcpy(buffer, data[i].from);
> +			to = func(buffer);
> +		}
> +		if (strcmp(to, data[i].to)) {
> +			error("FAIL: %s(%s) => '%s' != '%s'\n",
> +				funcname, data[i].from, to, data[i].to);
> +			failed = 1;
> +		}
> +	}
> +	return failed;
> +}
> +
> +static struct test_data basename_data[] = {
> +	/* --- POSIX type paths --- */
> +	{ NULL,              "."    },
> +	{ "",                "."    },
> +	{ ".",               "."    },
> +	{ "..",              ".."   },
> +	{ "/",               "/"    },
> +#if defined(__CYGWIN__) && !defined(NO_LIBGEN_H)
> +	{ "//",              "//"   },
> +	{ "///",             "//"   },
> +	{ "////",            "//"   },
> +#else
> +	{ "//",              "/"    },
> +	{ "///",             "/"    },
> +	{ "////",            "/"    },
> +#endif
> +	{ "usr",             "usr"  },
> +	{ "/usr",            "usr"  },
> +	{ "/usr/",           "usr"  },
> +	{ "/usr//",          "usr"  },
> +	{ "/usr/lib",        "lib"  },
> +	{ "usr/lib",         "lib"  },
> +	{ "usr/lib///",      "lib"  },
> +
> +#if defined(__MINGW32__) || defined(_MSC_VER)
> +
> +	/* --- win32 type paths --- */
> +	{ "\\usr",           "usr"  },
> +	{ "\\usr\\",         "usr"  },
> +	{ "\\usr\\\\",       "usr"  },
> +	{ "\\usr\\lib",      "lib"  },
> +	{ "usr\\lib",        "lib"  },
> +	{ "usr\\lib\\\\\\",  "lib"  },
> +	{ "C:/usr",          "usr"  },
> +	{ "C:/usr",          "usr"  },