diff --git a/.gitattributes b/.gitattributes
index b0044cf272..2bc4defac6 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -4,6 +4,7 @@
 *.perl eol=lf diff=perl
 *.pl eof=lf diff=perl
 *.pm eol=lf diff=perl
+*.png binary
 *.py eol=lf diff=python
 *.bat eol=crlf
 CODE_OF_CONDUCT.md -whitespace
diff --git a/Makefile b/Makefile
index 419e64bc29..d1993e2f9f 100644
--- a/Makefile
+++ b/Makefile
@@ -693,6 +693,7 @@ PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 TEST_BUILTINS_OBJS += test-advise.o
 TEST_BUILTINS_OBJS += test-bloom.o
 TEST_BUILTINS_OBJS += test-chmtime.o
+TEST_BUILTINS_OBJS += test-cmp.o
 TEST_BUILTINS_OBJS += test-config.o
 TEST_BUILTINS_OBJS += test-crontab.o
 TEST_BUILTINS_OBJS += test-ctype.o
@@ -711,6 +712,7 @@ TEST_BUILTINS_OBJS += test-genzeros.o
 TEST_BUILTINS_OBJS += test-hash-speed.o
 TEST_BUILTINS_OBJS += test-hash.o
 TEST_BUILTINS_OBJS += test-hashmap.o
+TEST_BUILTINS_OBJS += test-iconv.o
 TEST_BUILTINS_OBJS += test-index-version.o
 TEST_BUILTINS_OBJS += test-json-writer.o
 TEST_BUILTINS_OBJS += test-lazy-init-name-hash.o
diff --git a/compat/mingw.c b/compat/mingw.c
index c66c4586e4..baa3adf110 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -11,6 +11,7 @@
 #include "dir.h"
 #include "win32/fscache.h"
 #include "../attr.h"
+#include "../string-list.h"
 
 #define HCAST(type, handle) ((type)(intptr_t)handle)
 
@@ -1538,6 +1539,65 @@ static char *lookup_prog(const char *dir, int dirlen, const char *cmd,
 	return NULL;
 }
 
+static char *path_lookup(const char *cmd, int exe_only);
+
+static char *is_busybox_applet(const char *cmd)
+{
+	static struct string_list applets = STRING_LIST_INIT_DUP;
+	static char *busybox_path;
+	static int busybox_path_initialized;
+
+	/* Avoid infinite loop */
+	if (!strncasecmp(cmd, "busybox", 7) &&
+	    (!cmd[7] || !strcasecmp(cmd + 7, ".exe")))
+		return NULL;
+
+	if (!busybox_path_initialized) {
+		busybox_path = path_lookup("busybox.exe", 1);
+		busybox_path_initialized = 1;
+	}
+
+	/* Assume that sh is compiled in... */
+	if (!busybox_path || !strcasecmp(cmd, "sh"))
+		return xstrdup_or_null(busybox_path);
+
+	if (!applets.nr) {
+		struct child_process cp = CHILD_PROCESS_INIT;
+		struct strbuf buf = STRBUF_INIT;
+		char *p;
+
+		strvec_pushl(&cp.args, busybox_path, "--help", NULL);
+
+		if (capture_command(&cp, &buf, 2048)) {
+			string_list_append(&applets, "");
+			return NULL;
+		}
+
+		/* parse output */
+		p = strstr(buf.buf, "Currently defined functions:\n");
+		if (!p) {
+			warning("Could not parse output of busybox --help");
+			string_list_append(&applets, "");
+			return NULL;
+		}
+		p = strchrnul(p, '\n');
+		for (;;) {
+			size_t len;
+
+			p += strspn(p, "\n\t ,");
+			len = strcspn(p, "\n\t ,");
+			if (!len)
+				break;
+			p[len] = '\0';
+			string_list_insert(&applets, p);
+			p = p + len + 1;
+		}
+	}
+
+	return string_list_has_string(&applets, cmd) ?
+		xstrdup(busybox_path) : NULL;
+}
+
 /*
  * Determines the absolute path of cmd using the split path in path.
  * If cmd contains a slash or backslash, no lookup is performed.
@@ -1566,6 +1626,9 @@ static char *path_lookup(const char *cmd, int exe_only)
 		path = sep + 1;
 	}
 
+	if (!prog && !isexe)
+		prog = is_busybox_applet(cmd);
+
 	return prog;
 }
 
@@ -1765,8 +1828,8 @@ static int is_msys2_sh(const char *cmd)
 }
 
 static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaenv,
-			      const char *dir,
-			      int prepend_cmd, int fhin, int fhout, int fherr)
+			      const char *dir, const char *prepend_cmd,
+			      int fhin, int fhout, int fherr)
 {
 	static int restrict_handle_inheritance = -1;
 	STARTUPINFOEXW si;
@@ -1857,9 +1920,9 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 	/* concatenate argv, quoting args as we go */
 	strbuf_init(&args, 0);
 	if (prepend_cmd) {
-		char *quoted = (char *)quote_arg(cmd);
+		char *quoted = (char *)quote_arg(prepend_cmd);
 		strbuf_addstr(&args, quoted);
-		if (quoted != cmd)
+		if (quoted != prepend_cmd)
 			free(quoted);
 	}
 	for (; *argv; argv++) {
@@ -2018,7 +2081,8 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 	return (pid_t)pi.dwProcessId;
 }
 
-static pid_t mingw_spawnv(const char *cmd, const char **argv, int prepend_cmd)
+static pid_t mingw_spawnv(const char *cmd, const char **argv,
+			  const char *prepend_cmd)
 {
 	return mingw_spawnve_fd(cmd, argv, NULL, NULL, prepend_cmd, 0, 1, 2);
 }
@@ -2046,14 +2110,14 @@ pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **deltaenv,
 				pid = -1;
 			}
 			else {
-				pid = mingw_spawnve_fd(iprog, argv, deltaenv, dir, 1,
+				pid = mingw_spawnve_fd(iprog, argv, deltaenv, dir, interpr,
 						       fhin, fhout, fherr);
 				free(iprog);
 			}
 			argv[0] = argv0;
 		}
 		else
-			pid = mingw_spawnve_fd(prog, argv, deltaenv, dir, 0,
+			pid = mingw_spawnve_fd(prog, argv, deltaenv, dir, NULL,
 					       fhin, fhout, fherr);
 		free(prog);
 	}
@@ -2081,7 +2145,7 @@ static int try_shell_exec(const char *cmd, char *const *argv)
 		argv2[0] = (char *)cmd;	/* full path to the script file */
 		COPY_ARRAY(&argv2[1], &argv[1], argc);
 		exec_id = trace2_exec(prog, argv2);
-		pid = mingw_spawnv(prog, argv2, 1);
+		pid = mingw_spawnv(prog, argv2, interpr);
 		if (pid >= 0) {
 			int status;
 			if (waitpid(pid, &status, 0) < 0)
@@ -2105,7 +2169,7 @@ int mingw_execv(const char *cmd, char *const *argv)
 		int exec_id;
 
 		exec_id = trace2_exec(cmd, (const char **)argv);
-		pid = mingw_spawnv(cmd, (const char **)argv, 0);
+		pid = mingw_spawnv(cmd, (const char **)argv, NULL);
 		if (pid < 0) {
 			trace2_exec_result(exec_id, -1);
 			return -1;
diff --git a/config.mak.uname b/config.mak.uname
index a45a48efb6..e29ad56b8a 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -694,6 +694,62 @@ else
 		NO_CURL = YesPlease
 	endif
 endif
+ifeq (i686,$(uname_M))
+	MINGW_PREFIX := mingw32
+endif
+ifeq (x86_64,$(uname_M))
+	MINGW_PREFIX := mingw64
+endif
+
+	DESTDIR_WINDOWS = $(shell cygpath -aw '$(DESTDIR_SQ)')
+	DESTDIR_MIXED = $(shell cygpath -am '$(DESTDIR_SQ)')
+install-mingit-test-artifacts:
+	install -m755 -d '$(DESTDIR_SQ)/usr/bin'
+	printf '%s\n%s\n' >'$(DESTDIR_SQ)/usr/bin/perl' \
+		"#!/mingw64/bin/busybox sh" \
+		"exec \"$(shell cygpath -am /usr/bin/perl.exe)\" \"\$$@\""
+
+	install -m755 -d '$(DESTDIR_SQ)'
+	printf '%s%s\n%s\n%s\n%s\n%s\n' >'$(DESTDIR_SQ)/init.bat' \
+		"PATH=$(DESTDIR_WINDOWS)\\$(MINGW_PREFIX)\\bin;" \
+		"C:\\WINDOWS;C:\\WINDOWS\\system32" \
+		"@set GIT_TEST_INSTALLED=$(DESTDIR_MIXED)/$(MINGW_PREFIX)/bin" \
+		"@`echo "$(DESTDIR_WINDOWS)" | sed 's/:.*/:/'`" \
+		"@cd `echo "$(DESTDIR_WINDOWS)" | sed 's/^.://'`\\test-git\\t" \
+		"@echo Now, run 'helper\\test-run-command testsuite'"
+
+	install -m755 -d '$(DESTDIR_SQ)/test-git'
+	sed 's/^\(NO_PERL\|NO_PYTHON\)=.*/\1=YesPlease/' \
+		<GIT-BUILD-OPTIONS >'$(DESTDIR_SQ)/test-git/GIT-BUILD-OPTIONS'
+
+	install -m755 -d '$(DESTDIR_SQ)/test-git/t/helper'
+	install -m755 $(TEST_PROGRAMS) '$(DESTDIR_SQ)/test-git/t/helper'
+	(cd t && $(TAR) cf - t[0-9][0-9][0-9][0-9] lib-diff) | \
+	(cd '$(DESTDIR_SQ)/test-git/t' && $(TAR) xf -)
+	install -m755 t/t556x_common t/*.sh '$(DESTDIR_SQ)/test-git/t'
+
+	install -m755 -d '$(DESTDIR_SQ)/test-git/templates'
+	(cd templates && $(TAR) cf - blt) | \
+	(cd '$(DESTDIR_SQ)/test-git/templates' && $(TAR) xf -)
+
+	# po/build/locale for t0200
+	install -m755 -d '$(DESTDIR_SQ)/test-git/po/build/locale'
+	(cd po/build/locale && $(TAR) cf - .) | \
+	(cd '$(DESTDIR_SQ)/test-git/po/build/locale' && $(TAR) xf -)
+
+	# git-daemon.exe for t5802, git-http-backend.exe for t5560
+	install -m755 -d '$(DESTDIR_SQ)/$(MINGW_PREFIX)/bin'
+	install -m755 git-daemon.exe git-http-backend.exe \
+		'$(DESTDIR_SQ)/$(MINGW_PREFIX)/bin'
+
+	# git-upload-archive (dashed) for t5000
+	install -m755 -d '$(DESTDIR_SQ)/$(MINGW_PREFIX)/bin'
+	install -m755 git-upload-archive.exe '$(DESTDIR_SQ)/$(MINGW_PREFIX)/bin'
+
+	# git-difftool--helper for t7800
+	install -m755 -d '$(DESTDIR_SQ)/$(MINGW_PREFIX)/libexec/git-core'
+	install -m755 git-difftool--helper \
+		'$(DESTDIR_SQ)/$(MINGW_PREFIX)/libexec/git-core'
 endif
 ifeq ($(uname_S),QNX)
 	COMPAT_CFLAGS += -DSA_RESTART=0
diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index 10d9764185..6a19a3bfc4 100644
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -333,17 +333,30 @@ create_virtual_base() {
 # Platform specific tweaks to work around some commands
 case $(uname -s) in
 *MINGW*)
-	# Windows has its own (incompatible) sort and find
-	sort () {
-		/usr/bin/sort "$@"
-	}
-	find () {
-		/usr/bin/find "$@"
-	}
-	# git sees Windows-style pwd
-	pwd () {
-		builtin pwd -W
-	}
+	if test -x /usr/bin/sort
+	then
+		# Windows has its own (incompatible) sort; override
+		sort () {
+			/usr/bin/sort "$@"
+		}
+	fi
+	if test -x /usr/bin/find
+	then
+		# Windows has its own (incompatible) find; override
+		find () {
+			/usr/bin/find "$@"
+		}
+	fi
+	# On Windows, Git wants Windows paths. But /usr/bin/pwd spits out
+	# Unix-style paths. At least in Bash, we have a builtin pwd that
+	# understands the -W option to force "mixed" paths, i.e. with drive
+	# prefix but still with forward slashes. Let's use that, if available.
+	if type builtin >/dev/null 2>&1
+	then
+		pwd () {
+			builtin pwd -W
+		}
+	fi
 	is_absolute_path () {
 		case "$1" in
 		[/\\]* | [A-Za-z]:*)
diff --git a/t/helper/test-cmp.c b/t/helper/test-cmp.c
new file mode 100644
index 0000000000..1c646a54bf
--- /dev/null
+++ b/t/helper/test-cmp.c
@@ -0,0 +1,73 @@
+#include "test-tool.h"
+#include "git-compat-util.h"
+#include "strbuf.h"
+#include "gettext.h"
+#include "parse-options.h"
+#include "run-command.h"
+
+#ifdef WIN32
+#define NO_SUCH_DIR "\\\\.\\GLOBALROOT\\invalid"
+#else
+#define NO_SUCH_DIR "/dev/null"
+#endif
+
+static int run_diff(const char *path1, const char *path2)
+{
+	const char *argv[] = {
+		"diff", "--no-index", NULL, NULL, NULL
+	};
+	const char *env[] = {
+		"GIT_PAGER=cat",
+		"GIT_DIR=" NO_SUCH_DIR,
+		"HOME=" NO_SUCH_DIR,
+		NULL
+	};
+
+	argv[2] = path1;
+	argv[3] = path2;
+	return run_command_v_opt_cd_env(argv,
+					RUN_COMMAND_NO_STDIN | RUN_GIT_CMD,
+					NULL, env);
+}
+
+int cmd__cmp(int argc, const char **argv)
+{
+	FILE *f0, *f1;
+	struct strbuf b0 = STRBUF_INIT, b1 = STRBUF_INIT;
+
+	if (argc != 3)
+		die("Require exactly 2 arguments, got %d", argc);
+
+	if (!(f0 = !strcmp(argv[1], "-") ? stdin : fopen(argv[1], "r")))
+		return error_errno("could not open '%s'", argv[1]);
+	if (!(f1 = !strcmp(argv[2], "-") ? stdin : fopen(argv[2], "r"))) {
+		fclose(f0);
+		return error_errno("could not open '%s'", argv[2]);
+	}
+
+	for (;;) {
+		int r0 = strbuf_getline(&b0, f0);
+		int r1 = strbuf_getline(&b1, f1);
+
+		if (r0 == EOF) {
+			fclose(f0);
+			fclose(f1);
+			strbuf_release(&b0);
+			strbuf_release(&b1);
+			if (r1 == EOF)
+				return 0;
+cmp_failed:
+			if (!run_diff(argv[1], argv[2]))
+				die("Huh? 'diff --no-index %s %s' succeeded",
+				    argv[1], argv[2]);
+			return 1;
+		}
+		if (r1 == EOF || strbuf_cmp(&b0, &b1)) {
+			fclose(f0);
+			fclose(f1);
+			strbuf_release(&b0);
+			strbuf_release(&b1);
+			goto cmp_failed;
+		}
+	}
+}
diff --git a/t/helper/test-iconv.c b/t/helper/test-iconv.c
new file mode 100644
index 0000000000..d3c772fddf
--- /dev/null
+++ b/t/helper/test-iconv.c
@@ -0,0 +1,47 @@
+#include "test-tool.h"
+#include "git-compat-util.h"
+#include "strbuf.h"
+#include "gettext.h"
+#include "parse-options.h"
+#include "utf8.h"
+
+int cmd__iconv(int argc, const char **argv)
+{
+	struct strbuf buf = STRBUF_INIT;
+	char *from = NULL, *to = NULL, *p;
+	size_t len;
+	int ret = 0;
+	const char * const iconv_usage[] = {
+		N_("test-helper --iconv [<options>]"),
+		NULL
+	};
+	struct option options[] = {
+		OPT_STRING('f', "from-code", &from, "encoding", "from"),
+		OPT_STRING('t', "to-code", &to, "encoding", "to"),
+		OPT_END()
+	};
+
+	argc = parse_options(argc, argv, NULL, options,
+			iconv_usage, 0);
+
+	if (argc > 1 || !from || !to)
+		usage_with_options(iconv_usage, options);
+
+	if (!argc) {
+		if (strbuf_read(&buf, 0, 2048) < 0)
+			die_errno("Could not read from stdin");
+	} else if (strbuf_read_file(&buf, argv[0], 2048) < 0)
+		die_errno("Could not read from '%s'", argv[0]);
+
+	p = reencode_string_len(buf.buf, buf.len, to, from, &len);
+	if (!p)
+		die_errno("Could not reencode");
+	if (write(1, p, len) < 0)
+		ret = !!error_errno("Could not write %"PRIuMAX" bytes",
+				    (uintmax_t)len);
+
+	strbuf_release(&buf);
+	free(p);
+
+	return ret;
+}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 287aa60023..6f974b1154 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -17,6 +17,7 @@ static struct test_cmd cmds[] = {
 	{ "advise", cmd__advise_if_enabled },
 	{ "bloom", cmd__bloom },
 	{ "chmtime", cmd__chmtime },
+	{ "cmp", cmd__cmp },
 	{ "config", cmd__config },
 	{ "crontab", cmd__crontab },
 	{ "ctype", cmd__ctype },
@@ -34,6 +35,7 @@ static struct test_cmd cmds[] = {
 	{ "genzeros", cmd__genzeros },
 	{ "hashmap", cmd__hashmap },
 	{ "hash-speed", cmd__hash_speed },
+	{ "iconv", cmd__iconv },
 	{ "index-version", cmd__index_version },
 	{ "json-writer", cmd__json_writer },
 	{ "lazy-init-name-hash", cmd__lazy_init_name_hash },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 9ea4b31011..003534d02e 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -7,6 +7,7 @@
 int cmd__advise_if_enabled(int argc, const char **argv);
 int cmd__bloom(int argc, const char **argv);
 int cmd__chmtime(int argc, const char **argv);
+int cmd__cmp(int argc, const char **argv);
 int cmd__config(int argc, const char **argv);
 int cmd__crontab(int argc, const char **argv);
 int cmd__ctype(int argc, const char **argv);
@@ -24,6 +25,7 @@ int cmd__genrandom(int argc, const char **argv);
 int cmd__genzeros(int argc, const char **argv);
 int cmd__hashmap(int argc, const char **argv);
 int cmd__hash_speed(int argc, const char **argv);
+int cmd__iconv(int argc, const char **argv);
 int cmd__index_version(int argc, const char **argv);
 int cmd__json_writer(int argc, const char **argv);
 int cmd__lazy_init_name_hash(int argc, const char **argv);
diff --git a/t/interop/interop-lib.sh b/t/interop/interop-lib.sh
index 3e0a2911d4..dea8883821 100644
--- a/t/interop/interop-lib.sh
+++ b/t/interop/interop-lib.sh
@@ -4,6 +4,10 @@
 . ../../GIT-BUILD-OPTIONS
 INTEROP_ROOT=$(pwd)
 BUILD_ROOT=$INTEROP_ROOT/build
+case "$PATH" in
+*\;*) PATH_SEP=\; ;;
+*) PATH_SEP=: ;;
+esac
 
 build_version () {
 	if test -z "$1"
@@ -57,7 +61,7 @@ wrap_git () {
 	write_script "$1" <<-EOF
 	GIT_EXEC_PATH="$2"
 	export GIT_EXEC_PATH
-	PATH="$2:\$PATH"
+	PATH="$2$PATH_SEP\$PATH"
 	export GIT_EXEC_PATH
 	exec git "\$@"
 	EOF
@@ -71,7 +75,7 @@ generate_wrappers () {
 	echo >&2 fatal: test tried to run generic git
 	exit 1
 	EOF
-	PATH=$(pwd)/.bin:$PATH
+	PATH=$(pwd)/.bin$PATH_SEP$PATH
 }
 
 VERSION_A=${GIT_TEST_VERSION_A:-$VERSION_A}
diff --git a/t/test-binary-1.png b/t/lib-diff/test-binary-1.png
similarity index 100%
rename from t/test-binary-1.png
rename to t/lib-diff/test-binary-1.png
diff --git a/t/test-binary-2.png b/t/lib-diff/test-binary-2.png
similarity index 100%
rename from t/test-binary-2.png
rename to t/lib-diff/test-binary-2.png
diff --git a/t/lib-proto-disable.sh b/t/lib-proto-disable.sh
index 83babe57d9..9dc55a83a0 100644
--- a/t/lib-proto-disable.sh
+++ b/t/lib-proto-disable.sh
@@ -214,7 +214,7 @@ setup_ext_wrapper () {
 		cd "$TRASH_DIRECTORY/remote" &&
 		eval "$*"
 		EOF
-		PATH=$TRASH_DIRECTORY:$PATH &&
+		PATH=$TRASH_DIRECTORY$PATH_SEP$PATH &&
 		export TRASH_DIRECTORY
 	'
 }
diff --git a/t/t0014-alias.sh b/t/t0014-alias.sh
index 288e08299a..06669cab78 100755
--- a/t/t0014-alias.sh
+++ b/t/t0014-alias.sh
@@ -39,7 +39,7 @@ test_expect_success 'looping aliases - internal execution' '
 
 test_expect_success 'run-command formats empty args properly' '
 	test_must_fail env GIT_TRACE=1 git frotz a "" b " " c 2>actual.raw &&
-	sed -ne "/run_command:/s/.*trace: run_command: //p" actual.raw >actual &&
+	sed -ne "/run_command: git-frotz/s/.*trace: run_command: //p" actual.raw >actual &&
 	echo "git-frotz a '\'''\'' b '\'' '\'' c" >expect &&
 	test_cmp expect actual
 '
diff --git a/t/t0021-conversion.sh b/t/t0021-conversion.sh
index a9e10a0c21..1de07861d4 100755
--- a/t/t0021-conversion.sh
+++ b/t/t0021-conversion.sh
@@ -7,8 +7,8 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 . ./test-lib.sh
 
-TEST_ROOT="$PWD"
-PATH=$TEST_ROOT:$PATH
+TEST_ROOT="$(pwd)"
+PATH=$PWD$PATH_SEP$PATH
 
 write_script <<\EOF "$TEST_ROOT/rot13.sh"
 tr \
diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
index 97aaed0bd8..018a03fe68 100755
--- a/t/t0060-path-utils.sh
+++ b/t/t0060-path-utils.sh
@@ -135,25 +135,25 @@ ancestor /foo /fo -1
 ancestor /foo /foo -1
 ancestor /foo /bar -1
 ancestor /foo /foo/bar -1
-ancestor /foo /foo:/bar -1
-ancestor /foo /:/foo:/bar 0
-ancestor /foo /foo:/:/bar 0
-ancestor /foo /:/bar:/foo 0
+ancestor /foo "/foo$PATH_SEP/bar" -1
+ancestor /foo "/$PATH_SEP/foo$PATH_SEP/bar" 0
+ancestor /foo "/foo$PATH_SEP/$PATH_SEP/bar" 0
+ancestor /foo "/$PATH_SEP/bar$PATH_SEP/foo" 0
 ancestor /foo/bar / 0
 ancestor /foo/bar /fo -1
 ancestor /foo/bar /foo 4
 ancestor /foo/bar /foo/ba -1
-ancestor /foo/bar /:/fo 0
-ancestor /foo/bar /foo:/foo/ba 4
+ancestor /foo/bar "/$PATH_SEP/fo" 0
+ancestor /foo/bar "/foo$PATH_SEP/foo/ba" 4
 ancestor /foo/bar /bar -1
 ancestor /foo/bar /fo -1
-ancestor /foo/bar /foo:/bar 4
-ancestor /foo/bar /:/foo:/bar 4
-ancestor /foo/bar /foo:/:/bar 4
-ancestor /foo/bar /:/bar:/fo 0
-ancestor /foo/bar /:/bar 0
+ancestor /foo/bar "/foo$PATH_SEP/bar" 4
+ancestor /foo/bar "/$PATH_SEP/foo$PATH_SEP/bar" 4
+ancestor /foo/bar "/foo$PATH_SEP/$PATH_SEP/bar" 4
+ancestor /foo/bar "/$PATH_SEP/bar$PATH_SEP/fo" 0
+ancestor /foo/bar "/$PATH_SEP/bar" 0
 ancestor /foo/bar /foo 4
-ancestor /foo/bar /foo:/bar 4
+ancestor /foo/bar "/foo$PATH_SEP/bar" 4
 ancestor /foo/bar /bar -1
 
 test_expect_success 'strip_path_suffix' '
diff --git a/t/t0061-run-command.sh b/t/t0061-run-command.sh
index 7d599675e3..ea894b54ae 100755
--- a/t/t0061-run-command.sh
+++ b/t/t0061-run-command.sh
@@ -69,7 +69,7 @@ test_expect_success 'run_command does not try to execute a directory' '
 	cat bin2/greet
 	EOF
 
-	PATH=$PWD/bin1:$PWD/bin2:$PATH \
+	PATH=$PWD/bin1$PATH_SEP$PWD/bin2$PATH_SEP$PATH \
 		test-tool run-command run-command greet >actual 2>err &&
 	test_cmp bin2/greet actual &&
 	test_must_be_empty err
@@ -86,7 +86,7 @@ test_expect_success POSIXPERM 'run_command passes over non-executable file' '
 	cat bin2/greet
 	EOF
 
-	PATH=$PWD/bin1:$PWD/bin2:$PATH \
+	PATH=$PWD/bin1$PATH_SEP$PWD/bin2$PATH_SEP$PATH \
 		test-tool run-command run-command greet >actual 2>err &&
 	test_cmp bin2/greet actual &&
 	test_must_be_empty err
@@ -106,7 +106,7 @@ test_expect_success POSIXPERM,SANITY 'unreadable directory in PATH' '
 	git config alias.nitfol "!echo frotz" &&
 	chmod a-rx local-command &&
 	(
-		PATH=./local-command:$PATH &&
+		PATH=./local-command$PATH_SEP$PATH &&
 		git nitfol >actual
 	) &&
 	echo frotz >expect &&
diff --git a/t/t0300-credentials.sh b/t/t0300-credentials.sh
index 3485c0534e..ed045188e0 100755
--- a/t/t0300-credentials.sh
+++ b/t/t0300-credentials.sh
@@ -35,7 +35,7 @@ test_expect_success 'setup helper scripts' '
 	test -z "$pass" || echo password=$pass
 	EOF
 
-	PATH="$PWD:$PATH"
+	PATH="$PWD$PATH_SEP$PATH"
 '
 
 test_expect_success 'credential_fill invokes helper' '
diff --git a/t/t1504-ceiling-dirs.sh b/t/t1504-ceiling-dirs.sh
index 3d51615e42..dc84733451 100755
--- a/t/t1504-ceiling-dirs.sh
+++ b/t/t1504-ceiling-dirs.sh
@@ -79,9 +79,9 @@ then
 	GIT_CEILING_DIRECTORIES="$TRASH_ROOT/top/"
 	test_fail subdir_ceil_at_top_slash
 
-	GIT_CEILING_DIRECTORIES=":$TRASH_ROOT/top"
+	GIT_CEILING_DIRECTORIES="$PATH_SEP$TRASH_ROOT/top"
 	test_prefix subdir_ceil_at_top_no_resolve "sub/dir/"
-	GIT_CEILING_DIRECTORIES=":$TRASH_ROOT/top/"
+	GIT_CEILING_DIRECTORIES="$PATH_SEP$TRASH_ROOT/top/"
 	test_prefix subdir_ceil_at_top_slash_no_resolve "sub/dir/"
 fi
 
@@ -111,13 +111,13 @@ GIT_CEILING_DIRECTORIES="$TRASH_ROOT/subdi"
 test_prefix subdir_ceil_at_subdi_slash "sub/dir/"
 
 
-GIT_CEILING_DIRECTORIES="/foo:$TRASH_ROOT/sub"
+GIT_CEILING_DIRECTORIES="/foo$PATH_SEP$TRASH_ROOT/sub"
 test_fail second_of_two
 
-GIT_CEILING_DIRECTORIES="$TRASH_ROOT/sub:/bar"
+GIT_CEILING_DIRECTORIES="$TRASH_ROOT/sub$PATH_SEP/bar"
 test_fail first_of_two
 
-GIT_CEILING_DIRECTORIES="/foo:$TRASH_ROOT/sub:/bar"
+GIT_CEILING_DIRECTORIES="/foo$PATH_SEP$TRASH_ROOT/sub$PATH_SEP/bar"
 test_fail second_of_three
 
 
diff --git a/t/t2300-cd-to-toplevel.sh b/t/t2300-cd-to-toplevel.sh
index c8de6d8a19..91f523d519 100755
--- a/t/t2300-cd-to-toplevel.sh
+++ b/t/t2300-cd-to-toplevel.sh
@@ -16,7 +16,7 @@ test_cd_to_toplevel () {
 	test_expect_success $3 "$2" '
 		(
 			cd '"'$1'"' &&
-			PATH="$EXEC_PATH:$PATH" &&
+			PATH="$EXEC_PATH$PATH_SEP$PATH" &&
 			. git-sh-setup &&
 			cd_to_toplevel &&
 			[ "$(pwd -P)" = "$TOPLEVEL" ]
diff --git a/t/t3307-notes-man.sh b/t/t3307-notes-man.sh
index 1aa366a410..7e5c06e661 100755
--- a/t/t3307-notes-man.sh
+++ b/t/t3307-notes-man.sh
@@ -26,7 +26,7 @@ test_expect_success 'example 1: notes to add an Acked-by line' '
 '
 
 test_expect_success 'example 2: binary notes' '
-	cp "$TEST_DIRECTORY"/test-binary-1.png . &&
+	cp "$TEST_DIRECTORY"/lib-diff/test-binary-1.png . &&
 	git checkout B &&
 	blob=$(git hash-object -w test-binary-1.png) &&
 	git notes --ref=logo add -C "$blob" &&
diff --git a/t/t3402-rebase-merge.sh b/t/t3402-rebase-merge.sh
index cfde68f193..267443fd2c 100755
--- a/t/t3402-rebase-merge.sh
+++ b/t/t3402-rebase-merge.sh
@@ -146,7 +146,7 @@ test_expect_success 'rebase -s funny -Xopt' '
 	git checkout -b test-funny main^ &&
 	test_commit funny &&
 	(
-		PATH=./test-bin:$PATH &&
+		PATH=./test-bin$PATH_SEP$PATH &&
 		git rebase -s funny -Xopt main
 	) &&
 	test -f funny.was.run
diff --git a/t/t3418-rebase-continue.sh b/t/t3418-rebase-continue.sh
index 0838f4e798..5bafc759c6 100755
--- a/t/t3418-rebase-continue.sh
+++ b/t/t3418-rebase-continue.sh
@@ -63,7 +63,7 @@ test_expect_success 'rebase --continue remembers merge strategy and options' '
 	EOF
 	chmod +x test-bin/git-merge-funny &&
 	(
-		PATH=./test-bin:$PATH &&
+		PATH=./test-bin$PATH_SEP$PATH &&
 		test_must_fail git rebase -s funny -Xopt main topic
 	) &&
 	test -f funny.was.run &&
@@ -71,7 +71,7 @@ test_expect_success 'rebase --continue remembers merge strategy and options' '
 	echo "Resolved" >F2 &&
 	git add F2 &&
 	(
-		PATH=./test-bin:$PATH &&
+		PATH=./test-bin$PATH_SEP$PATH &&
 		git rebase --continue
 	) &&
 	test -f funny.was.run
@@ -95,7 +95,7 @@ test_expect_success 'rebase -i --continue handles merge strategy and options' '
 	EOF
 	chmod +x test-bin/git-merge-funny &&
 	(
-		PATH=./test-bin:$PATH &&
+		PATH=./test-bin$PATH_SEP$PATH &&
 		test_must_fail git rebase -i -s funny -Xopt -Xfoo main topic
 	) &&
 	test -f funny.was.run &&
@@ -103,7 +103,7 @@ test_expect_success 'rebase -i --continue handles merge strategy and options' '
 	echo "Resolved" >F2 &&
 	git add F2 &&
 	(
-		PATH=./test-bin:$PATH &&
+		PATH=./test-bin$PATH_SEP$PATH &&
 		git rebase --continue
 	) &&
 	test -f funny.was.run
diff --git a/t/t3903-stash.sh b/t/t3903-stash.sh
index 5f282ecf61..1896e22017 100755
--- a/t/t3903-stash.sh
+++ b/t/t3903-stash.sh
@@ -1213,7 +1213,7 @@ test_expect_success 'stash -- <subdir> works with binary files' '
 	git reset &&
 	>subdir/untracked &&
 	>subdir/tracked &&
-	cp "$TEST_DIRECTORY"/test-binary-1.png subdir/tracked-binary &&
+	cp "$TEST_DIRECTORY"/lib-diff/test-binary-1.png subdir/tracked-binary &&
 	git add subdir/tracked* &&
 	git stash -- subdir/ &&
 	test_path_is_missing subdir/tracked &&
diff --git a/t/t4012-diff-binary.sh b/t/t4012-diff-binary.sh
index 33ff588ebc..cec2b1ae0b 100755
--- a/t/t4012-diff-binary.sh
+++ b/t/t4012-diff-binary.sh
@@ -19,7 +19,7 @@ test_expect_success 'prepare repository' '
 	echo AIT >a && echo BIT >b && echo CIT >c && echo DIT >d &&
 	git update-index --add a b c d &&
 	echo git >a &&
-	cat "$TEST_DIRECTORY"/test-binary-1.png >b &&
+	cat "$TEST_DIRECTORY"/lib-diff/test-binary-1.png >b &&
 	echo git >c &&
 	cat b b >d
 '
diff --git a/t/t4022-diff-rewrite.sh b/t/t4022-diff-rewrite.sh
index 6d1c3d949c..78f6165401 100755
--- a/t/t4022-diff-rewrite.sh
+++ b/t/t4022-diff-rewrite.sh
@@ -6,12 +6,12 @@ test_description='rewrite diff'
 
 test_expect_success setup '
 
-	cat "$TEST_DIRECTORY"/../COPYING >test &&
+	cat "$TEST_DIRECTORY"/lib-diff/COPYING >test &&
 	git add test &&
 	tr \
 	  "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" \
 	  "nopqrstuvwxyzabcdefghijklmNOPQRSTUVWXYZABCDEFGHIJKLM" \
-	  <"$TEST_DIRECTORY"/../COPYING >test &&
+	  <"$TEST_DIRECTORY"/lib-diff/COPYING >test &&
 	echo "to be deleted" >test2 &&
 	blob=$(git hash-object test2) &&
 	blob=$(git rev-parse --short $blob) &&
diff --git a/t/t4023-diff-rename-typechange.sh b/t/t4023-diff-rename-typechange.sh
index 8c9823765e..0df254c0d4 100755
--- a/t/t4023-diff-rename-typechange.sh
+++ b/t/t4023-diff-rename-typechange.sh
@@ -7,21 +7,21 @@ test_description='typechange rename detection'
 test_expect_success setup '
 
 	rm -f foo bar &&
-	cat "$TEST_DIRECTORY"/../COPYING >foo &&
+	cat "$TEST_DIRECTORY"/lib-diff/COPYING >foo &&
 	test_ln_s_add linklink bar &&
 	git add foo &&
 	git commit -a -m Initial &&
 	git tag one &&
 
 	git rm -f foo bar &&
-	cat "$TEST_DIRECTORY"/../COPYING >bar &&
+	cat "$TEST_DIRECTORY"/lib-diff/COPYING >bar &&
 	test_ln_s_add linklink foo &&
 	git add bar &&
 	git commit -a -m Second &&
 	git tag two &&
 
 	git rm -f foo bar &&
-	cat "$TEST_DIRECTORY"/../COPYING >foo &&
+	cat "$TEST_DIRECTORY"/lib-diff/COPYING >foo &&
 	git add foo &&
 	git commit -a -m Third &&
 	git tag three &&
@@ -35,15 +35,15 @@ test_expect_success setup '
 	# This is purely for sanity check
 
 	git rm -f foo bar &&
-	cat "$TEST_DIRECTORY"/../COPYING >foo &&
-	cat "$TEST_DIRECTORY"/../Makefile >bar &&
+	cat "$TEST_DIRECTORY"/lib-diff/COPYING >foo &&
+	cat "$TEST_DIRECTORY"/lib-diff/README >bar &&
 	git add foo bar &&
 	git commit -a -m Fifth &&
 	git tag five &&
 
 	git rm -f foo bar &&
-	cat "$TEST_DIRECTORY"/../Makefile >foo &&
-	cat "$TEST_DIRECTORY"/../COPYING >bar &&
+	cat "$TEST_DIRECTORY"/lib-diff/README >foo &&
+	cat "$TEST_DIRECTORY"/lib-diff/COPYING >bar &&
 	git add foo bar &&
 	git commit -a -m Sixth &&
 	git tag six
diff --git a/t/t4049-diff-stat-count.sh b/t/t4049-diff-stat-count.sh
index 53061b104e..8bb22bf043 100755
--- a/t/t4049-diff-stat-count.sh
+++ b/t/t4049-diff-stat-count.sh
@@ -32,7 +32,7 @@ test_expect_success 'binary changes do not count in lines' '
 	git reset --hard &&
 	echo a >a &&
 	echo c >c &&
-	cat "$TEST_DIRECTORY"/test-binary-1.png >d &&
+	cat "$TEST_DIRECTORY"/lib-diff/test-binary-1.png >d &&
 	cat >expect <<-\EOF &&
 	 a | 1 +
 	 c | 1 +
diff --git a/t/t5003-archive-zip.sh b/t/t5003-archive-zip.sh
index 1e6d18b140..47c9461953 100755
--- a/t/t5003-archive-zip.sh
+++ b/t/t5003-archive-zip.sh
@@ -87,7 +87,7 @@ test_expect_success \
     'mkdir a &&
      echo simple textfile >a/a &&
      mkdir a/bin &&
-     cp /bin/sh a/bin &&
+     cp "$TEST_DIRECTORY/lib-diff/test-binary-1.png" a/bin &&
      printf "text\r"	>a/text.cr &&
      printf "text\r\n"	>a/text.crlf &&
      printf "text\n"	>a/text.lf &&
diff --git a/t/t5532-fetch-proxy.sh b/t/t5532-fetch-proxy.sh
index 9c2798603b..11fc3f2eea 100755
--- a/t/t5532-fetch-proxy.sh
+++ b/t/t5532-fetch-proxy.sh
@@ -25,7 +25,7 @@ test_expect_success 'setup proxy script' '
 
 	write_script proxy <<-\EOF
 	echo >&2 "proxying for $*"
-	cmd=$(./proxy-get-cmd)
+	cmd=$("$PERL_PATH" ./proxy-get-cmd)
 	echo >&2 "Running $cmd"
 	exec $cmd
 	EOF
diff --git a/t/t5605-clone-local.sh b/t/t5605-clone-local.sh
index 7d63365f93..673d50cbf8 100755
--- a/t/t5605-clone-local.sh
+++ b/t/t5605-clone-local.sh
@@ -11,6 +11,21 @@ repo_is_hardlinked() {
 	test_line_count = 0 output
 }
 
+if test_have_prereq MINGW,BUSYBOX
+then
+	# BusyBox' `find` does not support `-links`. Besides, BusyBox-w32's
+	# lstat() does not report hard links, just like Git's mingw_lstat()
+	# (from where BusyBox-w32 got its initial implementation).
+	repo_is_hardlinked() {
+		for f in $(find "$1/objects" -type f)
+		do
+			"$SYSTEMROOT"/system32/fsutil.exe \
+				hardlink list $f >links &&
+			test_line_count -gt 1 links || return 1
+		done
+	}
+fi
+
 test_expect_success 'preparing origin repository' '
 	: >file && git add . && git commit -m1 &&
 	git clone --bare . a.git &&
diff --git a/t/t5615-alternate-env.sh b/t/t5615-alternate-env.sh
index b4905b822c..8ce5e99c3a 100755
--- a/t/t5615-alternate-env.sh
+++ b/t/t5615-alternate-env.sh
@@ -38,7 +38,7 @@ test_expect_success 'access alternate via absolute path' '
 '
 
 test_expect_success 'access multiple alternates' '
-	check_obj "$PWD/one.git/objects:$PWD/two.git/objects" <<-EOF
+	check_obj "$PWD/one.git/objects$PATH_SEP$PWD/two.git/objects" <<-EOF
 	$one blob
 	$two blob
 	EOF
@@ -74,7 +74,7 @@ test_expect_success 'access alternate via relative path (subdir)' '
 quoted='"one.git\057objects"'
 unquoted='two.git/objects'
 test_expect_success 'mix of quoted and unquoted alternates' '
-	check_obj "$quoted:$unquoted" <<-EOF
+	check_obj "$quoted$PATH_SEP$unquoted" <<-EOF
 	$one blob
 	$two blob
 	EOF
diff --git a/t/t5802-connect-helper.sh b/t/t5802-connect-helper.sh
index c6c2661878..a096eeeeb4 100755
--- a/t/t5802-connect-helper.sh
+++ b/t/t5802-connect-helper.sh
@@ -85,7 +85,7 @@ test_expect_success 'set up fake git-daemon' '
 		"$TRASH_DIRECTORY/remote"
 	EOF
 	export TRASH_DIRECTORY &&
-	PATH=$TRASH_DIRECTORY:$PATH
+	PATH=$TRASH_DIRECTORY$PATH_SEP$PATH
 '
 
 test_expect_success 'ext command can connect to git daemon (no vhost)' '
diff --git a/t/t5813-proto-disable-ssh.sh b/t/t5813-proto-disable-ssh.sh
index 3f084ee306..0a2c77093b 100755
--- a/t/t5813-proto-disable-ssh.sh
+++ b/t/t5813-proto-disable-ssh.sh
@@ -14,8 +14,23 @@ test_expect_success 'setup repository to clone' '
 '
 
 test_proto "host:path" ssh "remote:repo.git"
-test_proto "ssh://" ssh "ssh://remote$PWD/remote/repo.git"
-test_proto "git+ssh://" ssh "git+ssh://remote$PWD/remote/repo.git"
+
+hostdir="$PWD"
+if test_have_prereq MINGW && test "/${PWD#/}" != "$PWD"
+then
+	case "$PWD" in
+	[A-Za-z]:/*)
+		hostdir="${PWD#?:}"
+		;;
+	*)
+		skip_all="Unhandled PWD '$PWD'; skipping rest"
+		test_done
+		;;
+	esac
+fi
+
+test_proto "ssh://" ssh "ssh://remote$hostdir/remote/repo.git"
+test_proto "git+ssh://" ssh "git+ssh://remote$hostdir/remote/repo.git"
 
 # Don't even bother setting up a "-remote" directory, as ssh would generally
 # complain about the bogus option rather than completing our request. Our
diff --git a/t/t6403-merge-file.sh b/t/t6403-merge-file.sh
index 2f421d967a..52e29f9713 100755
--- a/t/t6403-merge-file.sh
+++ b/t/t6403-merge-file.sh
@@ -250,7 +250,7 @@ test_expect_success "expected conflict markers" '
 
 test_expect_success 'binary files cannot be merged' '
 	test_must_fail git merge-file -p \
-		orig.txt "$TEST_DIRECTORY"/test-binary-1.png new1.txt 2> merge.err &&
+		orig.txt "$TEST_DIRECTORY"/lib-diff/test-binary-1.png new1.txt 2> merge.err &&
 	grep "Cannot merge binary files" merge.err
 '
 
diff --git a/t/t6407-merge-binary.sh b/t/t6407-merge-binary.sh
index d4273f2575..3cfe6eeb79 100755
--- a/t/t6407-merge-binary.sh
+++ b/t/t6407-merge-binary.sh
@@ -9,7 +9,7 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 test_expect_success setup '
 
-	cat "$TEST_DIRECTORY"/test-binary-1.png >m &&
+	cat "$TEST_DIRECTORY"/lib-diff/test-binary-1.png >m &&
 	git add m &&
 	git ls-files -s | sed -e "s/ 0	/ 1	/" >E1 &&
 	test_tick &&
diff --git a/t/t7001-mv.sh b/t/t7001-mv.sh
index 25bb9bbb89..d59b867573 100755
--- a/t/t7001-mv.sh
+++ b/t/t7001-mv.sh
@@ -5,7 +5,7 @@ test_description='git mv in subdirs'
 
 test_expect_success 'prepare reference tree' '
 	mkdir path0 path1 &&
-	cp "$TEST_DIRECTORY"/../COPYING path0/COPYING &&
+	cp "$TEST_DIRECTORY"/lib-diff/COPYING path0/COPYING &&
 	git add path0/COPYING &&
 	git commit -m add -a
 '
@@ -107,7 +107,7 @@ test_expect_success 'clean up' '
 '
 
 test_expect_success 'adding another file' '
-	cp "$TEST_DIRECTORY"/../README.md path0/README &&
+	cp "$TEST_DIRECTORY"/lib-diff/README path0/ &&
 	git add path0/README &&
 	git commit -m add2 -a
 '
diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
index 0e7cf75435..4e6979ba0b 100755
--- a/t/t7006-pager.sh
+++ b/t/t7006-pager.sh
@@ -54,7 +54,7 @@ test_expect_success !MINGW,TTY 'LESS and LV envvars set by git-sh-setup' '
 		sane_unset LESS LV &&
 		PAGER="env >pager-env.out; wc" &&
 		export PAGER &&
-		PATH="$(git --exec-path):$PATH" &&
+		PATH="$(git --exec-path)$PATH_SEP$PATH" &&
 		export PATH &&
 		test_terminal sh -c ". git-sh-setup && git_pager"
 	) &&
@@ -388,7 +388,7 @@ test_default_pager() {
 		EOF
 		chmod +x \$less &&
 		(
-			PATH=.:\$PATH &&
+			PATH=.$PATH_SEP\$PATH &&
 			export PATH &&
 			$full_command
 		) &&
diff --git a/t/t7060-wtstatus.sh b/t/t7060-wtstatus.sh
index 0f4344c55e..753ca33d52 100755
--- a/t/t7060-wtstatus.sh
+++ b/t/t7060-wtstatus.sh
@@ -64,7 +64,7 @@ EOF
 
 test_expect_success 'rename & unmerged setup' '
 	git rm -f -r . &&
-	cat "$TEST_DIRECTORY/README" >ONE &&
+	cat "$TEST_DIRECTORY/lib-diff/README" >ONE &&
 	git add ONE &&
 	test_tick &&
 	git commit -m "One commit with ONE" &&
diff --git a/t/t7101-reset-empty-subdirs.sh b/t/t7101-reset-empty-subdirs.sh
index bfce05ac5d..91fb1bf999 100755
--- a/t/t7101-reset-empty-subdirs.sh
+++ b/t/t7101-reset-empty-subdirs.sh
@@ -8,7 +8,7 @@ test_description='git reset should cull empty subdirs'
 
 test_expect_success 'creating initial files' '
      mkdir path0 &&
-     cp "$TEST_DIRECTORY"/../COPYING path0/COPYING &&
+     cp "$TEST_DIRECTORY"/lib-diff/COPYING path0/COPYING &&
      git add path0/COPYING &&
      git commit -m add -a
 '
@@ -16,10 +16,10 @@ test_expect_success 'creating initial files' '
 test_expect_success 'creating second files' '
      mkdir path1 &&
      mkdir path1/path2 &&
-     cp "$TEST_DIRECTORY"/../COPYING path1/path2/COPYING &&
-     cp "$TEST_DIRECTORY"/../COPYING path1/COPYING &&
-     cp "$TEST_DIRECTORY"/../COPYING COPYING &&
-     cp "$TEST_DIRECTORY"/../COPYING path0/COPYING-TOO &&
+     cp "$TEST_DIRECTORY"/lib-diff/COPYING path1/path2/COPYING &&
+     cp "$TEST_DIRECTORY"/lib-diff/COPYING path1/COPYING &&
+     cp "$TEST_DIRECTORY"/lib-diff/COPYING COPYING &&
+     cp "$TEST_DIRECTORY"/lib-diff/COPYING path0/COPYING-TOO &&
      git add path1/path2/COPYING &&
      git add path1/COPYING &&
      git add COPYING &&
diff --git a/t/t7606-merge-custom.sh b/t/t7606-merge-custom.sh
index 81fb7c474c..8197a1c46b 100755
--- a/t/t7606-merge-custom.sh
+++ b/t/t7606-merge-custom.sh
@@ -23,7 +23,7 @@ test_expect_success 'set up custom strategy' '
 	EOF
 
 	chmod +x git-merge-theirs &&
-	PATH=.:$PATH &&
+	PATH=.$PATH_SEP$PATH &&
 	export PATH
 '
 
diff --git a/t/t7811-grep-open.sh b/t/t7811-grep-open.sh
index a98785da79..45bfa7ee60 100755
--- a/t/t7811-grep-open.sh
+++ b/t/t7811-grep-open.sh
@@ -52,7 +52,7 @@ test_expect_success SIMPLEPAGER 'git grep -O' '
 	EOF
 	echo grep.h >expect.notless &&
 
-	PATH=.:$PATH git grep -O GREP_PATTERN >out &&
+	PATH=.$PATH_SEP$PATH git grep -O GREP_PATTERN >out &&
 	{
 		test_cmp expect.less pager-args ||
 		test_cmp expect.notless pager-args
diff --git a/t/t9003-help-autocorrect.sh b/t/t9003-help-autocorrect.sh
index f00deaf381..982aac7d16 100755
--- a/t/t9003-help-autocorrect.sh
+++ b/t/t9003-help-autocorrect.sh
@@ -12,7 +12,7 @@ test_expect_success 'setup' '
 		echo distimdistim was called
 	EOF
 
-	PATH="$PATH:." &&
+	PATH="$PATH$PATH_SEP." &&
 	export PATH &&
 
 	git commit --allow-empty -m "a single log entry" &&
diff --git a/t/t9200-git-cvsexportcommit.sh b/t/t9200-git-cvsexportcommit.sh
index c5946cb0b8..450ff1c2bc 100755
--- a/t/t9200-git-cvsexportcommit.sh
+++ b/t/t9200-git-cvsexportcommit.sh
@@ -11,6 +11,13 @@ if ! test_have_prereq PERL; then
 	test_done
 fi
 
+case "$PWD" in
+*:*)
+	skip_all='cvs would get confused by the colon in `pwd`; skipping tests'
+	test_done
+	;;
+esac
+
 cvs >/dev/null 2>&1
 if test $? -ne 1
 then
@@ -55,8 +62,8 @@ test_expect_success \
     'mkdir A B C D E F &&
      echo hello1 >A/newfile1.txt &&
      echo hello2 >B/newfile2.txt &&
-     cp "$TEST_DIRECTORY"/test-binary-1.png C/newfile3.png &&
-     cp "$TEST_DIRECTORY"/test-binary-1.png D/newfile4.png &&
+     cp "$TEST_DIRECTORY"/lib-diff/test-binary-1.png C/newfile3.png &&
+     cp "$TEST_DIRECTORY"/lib-diff/test-binary-1.png D/newfile4.png &&
      git add A/newfile1.txt &&
      git add B/newfile2.txt &&
      git add C/newfile3.png &&
@@ -81,8 +88,8 @@ test_expect_success \
      rm -f B/newfile2.txt &&
      rm -f C/newfile3.png &&
      echo Hello5  >E/newfile5.txt &&
-     cp "$TEST_DIRECTORY"/test-binary-2.png D/newfile4.png &&
-     cp "$TEST_DIRECTORY"/test-binary-1.png F/newfile6.png &&
+     cp "$TEST_DIRECTORY"/lib-diff/test-binary-2.png D/newfile4.png &&
+     cp "$TEST_DIRECTORY"/lib-diff/test-binary-1.png F/newfile6.png &&
      git add E/newfile5.txt &&
      git add F/newfile6.png &&
      git commit -a -m "Test: Remove, add and update" &&
@@ -170,7 +177,7 @@ test_expect_success \
      'mkdir "G g" &&
       echo ok then >"G g/with spaces.txt" &&
       git add "G g/with spaces.txt" && \
-      cp "$TEST_DIRECTORY"/test-binary-1.png "G g/with spaces.png" && \
+      cp "$TEST_DIRECTORY"/lib-diff/test-binary-1.png "G g/with spaces.png" && \
       git add "G g/with spaces.png" &&
       git commit -a -m "With spaces" &&
       id=$(git rev-list --max-count=1 HEAD) &&
@@ -182,7 +189,8 @@ test_expect_success \
 test_expect_success \
      'Update file with spaces in file name' \
      'echo Ok then >>"G g/with spaces.txt" &&
-      cat "$TEST_DIRECTORY"/test-binary-1.png >>"G g/with spaces.png" && \
+      cat "$TEST_DIRECTORY"/lib-diff/test-binary-1.png \
+	>>"G g/with spaces.png" && \
       git add "G g/with spaces.png" &&
       git commit -a -m "Update with spaces" &&
       id=$(git rev-list --max-count=1 HEAD) &&
@@ -207,7 +215,7 @@ test_expect_success !MINGW \
      'mkdir -p Å/goo/a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y/z/å/ä/ö &&
       echo Foo >Å/goo/a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y/z/å/ä/ö/gårdetsågårdet.txt &&
       git add Å/goo/a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y/z/å/ä/ö/gårdetsågårdet.txt &&
-      cp "$TEST_DIRECTORY"/test-binary-1.png Å/goo/a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y/z/å/ä/ö/gårdetsågårdet.png &&
+      cp "$TEST_DIRECTORY"/lib-diff/test-binary-1.png Å/goo/a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y/z/å/ä/ö/gårdetsågårdet.png &&
       git add Å/goo/a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y/z/å/ä/ö/gårdetsågårdet.png &&
       git commit -a -m "Går det så går det" && \
       id=$(git rev-list --max-count=1 HEAD) &&
diff --git a/t/t9800-git-p4-basic.sh b/t/t9800-git-p4-basic.sh
index 81bc8e8da1..86095f98df 100755
--- a/t/t9800-git-p4-basic.sh
+++ b/t/t9800-git-p4-basic.sh
@@ -201,7 +201,7 @@ test_expect_success 'exit when p4 fails to produce marshaled output' '
 	EOF
 	chmod 755 badp4dir/p4 &&
 	(
-		PATH="$TRASH_DIRECTORY/badp4dir:$PATH" &&
+		PATH="$TRASH_DIRECTORY/badp4dir$PATH_SEP$PATH" &&
 		export PATH &&
 		test_expect_code 1 git p4 clone --dest="$git" //depot >errs 2>&1
 	) &&
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 04ce884ef5..1583401abb 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -129,12 +129,7 @@ invalid_variable_name='${foo.bar}'
 
 actual="$TRASH_DIRECTORY/actual"
 
-if test_have_prereq MINGW
-then
-	ROOT="$(pwd -W)"
-else
-	ROOT="$(pwd)"
-fi
+ROOT="$(pwd)"
 
 test_expect_success 'setup for __git_find_repo_path/__gitdir tests' '
 	mkdir -p subdir/subsubdir &&
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 6348e8d733..6785d0fd34 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -992,7 +992,7 @@ test_expect_code () {
 
 test_cmp () {
 	test "$#" -ne 2 && BUG "2 param"
-	eval "$GIT_TEST_CMP" '"$@"'
+	GIT_ALLOC_LIMIT=0 eval "$GIT_TEST_CMP" '"$@"'
 }
 
 # Check that the given config key has the expected value.
@@ -1312,72 +1312,6 @@ test_skip_or_die () {
 	error "$2"
 }
 
-# The following mingw_* functions obey POSIX shell syntax, but are actually
-# bash scripts, and are meant to be used only with bash on Windows.
-
-# A test_cmp function that treats LF and CRLF equal and avoids to fork
-# diff when possible.
-mingw_test_cmp () {
-	# Read text into shell variables and compare them. If the results
-	# are different, use regular diff to report the difference.
-	local test_cmp_a= test_cmp_b=
-
-	# When text came from stdin (one argument is '-') we must feed it
-	# to diff.
-	local stdin_for_diff=
-
-	# Since it is difficult to detect the difference between an
-	# empty input file and a failure to read the files, we go straight
-	# to diff if one of the inputs is empty.
-	if test -s "$1" && test -s "$2"
-	then
-		# regular case: both files non-empty
-		mingw_read_file_strip_cr_ test_cmp_a <"$1"
-		mingw_read_file_strip_cr_ test_cmp_b <"$2"
-	elif test -s "$1" && test "$2" = -
-	then
-		# read 2nd file from stdin
-		mingw_read_file_strip_cr_ test_cmp_a <"$1"
-		mingw_read_file_strip_cr_ test_cmp_b
-		stdin_for_diff='<<<"$test_cmp_b"'
-	elif test "$1" = - && test -s "$2"
-	then
-		# read 1st file from stdin
-		mingw_read_file_strip_cr_ test_cmp_a
-		mingw_read_file_strip_cr_ test_cmp_b <"$2"
-		stdin_for_diff='<<<"$test_cmp_a"'
-	fi
-	test -n "$test_cmp_a" &&
-	test -n "$test_cmp_b" &&
-	test "$test_cmp_a" = "$test_cmp_b" ||
-	eval "diff -u \"\$@\" $stdin_for_diff"
-}
-
-# $1 is the name of the shell variable to fill in
-mingw_read_file_strip_cr_ () {
-	# Read line-wise using LF as the line separator
-	# and use IFS to strip CR.
-	local line
-	while :
-	do
-		if IFS=$'\r' read -r -d $'\n' line
-		then
-			# good
-			line=$line$'\n'
-		else
-			# we get here at EOF, but also if the last line
-			# was not terminated by LF; in the latter case,
-			# some text was read
-			if test -z "$line"
-			then
-				# EOF, really
-				break
-			fi
-		fi
-		eval "$1=\$$1\$line"
-	done
-}
-
 # Like "env FOO=BAR some-program", but run inside a subshell, which means
 # it also works for shell functions (though those functions cannot impact
 # the environment outside of the test_env invocation).
diff --git a/t/test-lib.sh b/t/test-lib.sh
index d3f6af6a65..c8f16b8c45 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -15,6 +15,15 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see http://www.gnu.org/licenses/ .
 
+# On Unix/Linux, the path separator is the colon, on other systems it
+# may be different, though. On Windows, for example, it is a semicolon.
+# If the PATH variable contains semicolons, it is pretty safe to assume
+# that the path separator is a semicolon.
+case "$PATH" in
+*\;*) PATH_SEP=\; ;;
+*) PATH_SEP=: ;;
+esac
+
 # Test the binaries we have just built.  The tests are kept in
 # t/ subdirectory and are run in 'trash directory' subdirectory.
 if test -z "$TEST_DIRECTORY"
@@ -408,23 +417,18 @@ EDITOR=:
 # /usr/xpg4/bin/sh and /bin/ksh to bail out.  So keep the unsets
 # deriving from the command substitution clustered with the other
 # ones.
-unset VISUAL EMAIL LANGUAGE COLUMNS $("$PERL_PATH" -e '
-	my @env = keys %ENV;
-	my $ok = join("|", qw(
-		TRACE
-		DEBUG
-		TEST
-		.*_TEST
-		PROVE
-		VALGRIND
-		UNZIP
-		PERF_
-		CURL_VERBOSE
-		TRACE_CURL
-	));
-	my @vars = grep(/^GIT_/ && !/^GIT_($ok)/o, @env);
-	print join("\n", @vars);
-')
+unset VISUAL EMAIL LANGUAGE COLUMNS $(env | sed -n \
+	-e '/^GIT_TRACE/d' \
+	-e '/^GIT_DEBUG/d' \
+	-e '/^GIT_TEST/d' \
+	-e '/^GIT_.*_TEST/d' \
+	-e '/^GIT_PROVE/d' \
+	-e '/^GIT_VALGRIND/d' \
+	-e '/^GIT_UNZIP/d' \
+	-e '/^GIT_PERF_/d' \
+	-e '/^GIT_CURL_VERBOSE/d' \
+	-e '/^GIT_TRACE_CURL/d' \
+	-e 's/^\(GIT_[^=]*\)=.*/\1/p')
 unset XDG_CACHE_HOME
 unset XDG_CONFIG_HOME
 unset GITPERLLIB
@@ -1268,7 +1272,7 @@ then
 		done
 	done
 	IFS=$OLDIFS
-	PATH=$GIT_VALGRIND/bin:$PATH
+	PATH=$GIT_VALGRIND/bin$PATH_SEP$PATH
 	GIT_EXEC_PATH=$GIT_VALGRIND/bin
 	export GIT_VALGRIND
 	GIT_VALGRIND_MODE="$valgrind"
@@ -1280,7 +1284,7 @@ elif test -n "$GIT_TEST_INSTALLED"
 then
 	GIT_EXEC_PATH=$($GIT_TEST_INSTALLED/git --exec-path)  ||
 	error "Cannot run git from $GIT_TEST_INSTALLED."
-	PATH=$GIT_TEST_INSTALLED:$GIT_BUILD_DIR/t/helper:$PATH
+	PATH=$GIT_TEST_INSTALLED$PATH_SEP$GIT_BUILD_DIR/t/helper$PATH_SEP$PATH
 	GIT_EXEC_PATH=${GIT_TEST_EXEC_PATH:-$GIT_EXEC_PATH}
 else # normal case, use ../bin-wrappers only unless $with_dashes:
 	if test -n "$no_bin_wrappers"
@@ -1296,12 +1300,12 @@ else # normal case, use ../bin-wrappers only unless $with_dashes:
 			fi
 			with_dashes=t
 		fi
-		PATH="$git_bin_dir:$PATH"
+		PATH="$git_bin_dir$PATH_SEP$PATH"
 	fi
 	GIT_EXEC_PATH=$GIT_BUILD_DIR
 	if test -n "$with_dashes"
 	then
-		PATH="$GIT_BUILD_DIR:$GIT_BUILD_DIR/t/helper:$PATH"
+		PATH="$GIT_BUILD_DIR$PATH_SEP$GIT_BUILD_DIR/t/helper$PATH_SEP$PATH"
 	fi
 fi
 GIT_TEMPLATE_DIR="$GIT_BUILD_DIR"/templates/blt
@@ -1439,17 +1443,30 @@ fi
 uname_s=$(uname -s)
 case $uname_s in
 *MINGW*)
-	# Windows has its own (incompatible) sort and find
-	sort () {
-		/usr/bin/sort "$@"
-	}
-	find () {
-		/usr/bin/find "$@"
-	}
-	# git sees Windows-style pwd
-	pwd () {
-		builtin pwd -W
-	}
+	if test -x /usr/bin/sort
+	then
+		# Windows has its own (incompatible) sort; override
+		sort () {
+			/usr/bin/sort "$@"
+		}
+	fi
+	if test -x /usr/bin/find
+	then
+		# Windows has its own (incompatible) find; override
+		find () {
+			/usr/bin/find "$@"
+		}
+	fi
+	# On Windows, Git wants Windows paths. But /usr/bin/pwd spits out
+	# Unix-style paths. At least in Bash, we have a builtin pwd that
+	# understands the -W option to force "mixed" paths, i.e. with drive
+	# prefix but still with forward slashes. Let's use that, if available.
+	if type builtin >/dev/null 2>&1
+	then
+		pwd () {
+			builtin pwd -W
+		}
+	fi
 	# no POSIX permissions
 	# backslashes in pathspec are converted to '/'
 	# exec does not inherit the PID
@@ -1457,7 +1474,13 @@ case $uname_s in
 	test_set_prereq NATIVE_CRLF
 	test_set_prereq SED_STRIPS_CR
 	test_set_prereq GREP_STRIPS_CR
-	GIT_TEST_CMP=mingw_test_cmp
+	GIT_TEST_CMP="test-tool cmp"
+	if ! type iconv >/dev/null 2>&1
+	then
+		iconv () {
+			test-tool iconv "$@"
+		}
+	fi
 	;;
 *CYGWIN*)
 	test_set_prereq POSIXPERM
@@ -1603,6 +1626,10 @@ test_lazy_prereq UNZIP '
 	test $? -ne 127
 '
 
+test_lazy_prereq BUSYBOX '
+	case "$($SHELL --help 2>&1)" in *BusyBox*) true;; *) false;; esac
+'
+
 run_with_limited_cmdline () {
 	(ulimit -s 128 && "$@")
 }