thodg/libgit2

diff --git a/src/fs_path.c b/src/fs_path.c
index c9f03a7..f9da304 100644
--- a/src/fs_path.c
+++ b/src/fs_path.c
@@ -1851,3 +1851,59 @@ cleanup:
 	return ret;
 #endif
 }
+
+int git_fs_path_find_executable(git_str *fullpath, const char *executable)
+{
+#ifdef GIT_WIN32
+	git_win32_path fullpath_w, executable_w;
+	int error;
+
+	if (git__utf8_to_16(executable_w, GIT_WIN_PATH_MAX, executable) < 0)
+		return -1;
+
+	error = git_win32_path_find_executable(fullpath_w, executable_w);
+
+	if (error == 0)
+		error = git_str_put_w(fullpath, fullpath_w, wcslen(fullpath_w));
+
+	return error;
+#else
+	git_str path = GIT_STR_INIT;
+	const char *current_dir, *term;
+	bool found = false;
+
+	if (git__getenv(&path, "PATH") < 0)
+		return -1;
+
+	current_dir = path.ptr;
+
+	while (*current_dir) {
+		if (! (term = strchr(current_dir, GIT_PATH_LIST_SEPARATOR)))
+			term = strchr(current_dir, '\0');
+
+		git_str_clear(fullpath);
+		if (git_str_put(fullpath, current_dir, (term - current_dir)) < 0 ||
+		    git_str_putc(fullpath, '/') < 0 ||
+		    git_str_puts(fullpath, executable) < 0)
+			return -1;
+
+		if (git_fs_path_isfile(fullpath->ptr)) {
+			found = true;
+			break;
+		}
+
+		current_dir = term;
+
+		while (*current_dir == GIT_PATH_LIST_SEPARATOR)
+			current_dir++;
+	}
+
+	git_str_dispose(&path);
+
+	if (found)
+		return 0;
+
+	git_str_clear(fullpath);
+	return GIT_ENOTFOUND;
+#endif
+}
diff --git a/src/fs_path.h b/src/fs_path.h
index 9720d34..222c44a 100644
--- a/src/fs_path.h
+++ b/src/fs_path.h
@@ -743,4 +743,10 @@ bool git_fs_path_supports_symlinks(const char *dir);
  */
 int git_fs_path_validate_system_file_ownership(const char *path);
 
+/**
+ * Search the current PATH for the given executable, returning the full
+ * path if it is found.
+ */
+int git_fs_path_find_executable(git_str *fullpath, const char *executable);
+
 #endif
diff --git a/src/sysdir.c b/src/sysdir.c
index 84d212e..450cb50 100644
--- a/src/sysdir.c
+++ b/src/sysdir.c
@@ -31,7 +31,7 @@ static int git_sysdir_guess_programdata_dirs(git_str *out)
 static int git_sysdir_guess_system_dirs(git_str *out)
 {
 #ifdef GIT_WIN32
-	return git_win32__find_system_dirs(out, L"etc\\");
+	return git_win32__find_system_dirs(out, "etc");
 #else
 	return git_str_sets(out, "/etc");
 #endif
@@ -154,7 +154,7 @@ static int git_sysdir_guess_xdg_dirs(git_str *out)
 static int git_sysdir_guess_template_dirs(git_str *out)
 {
 #ifdef GIT_WIN32
-	return git_win32__find_system_dirs(out, L"share\\git-core\\templates");
+	return git_win32__find_system_dirs(out, "share/git-core/templates");
 #else
 	return git_str_sets(out, "/usr/share/git-core/templates");
 #endif
@@ -189,9 +189,25 @@ int git_sysdir_global_init(void)
 	for (i = 0; !error && i < ARRAY_SIZE(git_sysdir__dirs); i++)
 		error = git_sysdir__dirs[i].guess(&git_sysdir__dirs[i].buf);
 
+	if (error)
+		return error;
+
 	return git_runtime_shutdown_register(git_sysdir_global_shutdown);
 }
 
+int git_sysdir_reset(void)
+{
+	size_t i;
+	int error = 0;
+
+	for (i = 0; !error && i < ARRAY_SIZE(git_sysdir__dirs); ++i) {
+		git_str_dispose(&git_sysdir__dirs[i].buf);
+		error = git_sysdir__dirs[i].guess(&git_sysdir__dirs[i].buf);
+	}
+
+	return error;
+}
+
 static int git_sysdir_check_selector(git_sysdir_t which)
 {
 	if (which < ARRAY_SIZE(git_sysdir__dirs))
diff --git a/src/sysdir.h b/src/sysdir.h
index 43392a0..568f279 100644
--- a/src/sysdir.h
+++ b/src/sysdir.h
@@ -105,4 +105,9 @@ extern int git_sysdir_get(const git_str **out, git_sysdir_t which);
  */
 extern int git_sysdir_set(git_sysdir_t which, const char *paths);
 
+/**
+ * Reset search paths for global/system/xdg files.
+ */
+extern int git_sysdir_reset(void);
+
 #endif
diff --git a/src/win32/findfile.c b/src/win32/findfile.c
index d4afc4a..516391d 100644
--- a/src/win32/findfile.c
+++ b/src/win32/findfile.c
@@ -11,24 +11,14 @@
 #include "utf-conv.h"
 #include "fs_path.h"
 
-#define REG_MSYSGIT_INSTALL_LOCAL L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\Git_is1"
+#define REG_GITFORWINDOWS_KEY       L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\Git_is1"
+#define REG_GITFORWINDOWS_KEY_WOW64 L"SOFTWARE\\Wow6432Node\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\Git_is1"
 
-#ifndef _WIN64
-#define REG_MSYSGIT_INSTALL REG_MSYSGIT_INSTALL_LOCAL
-#else
-#define REG_MSYSGIT_INSTALL L"SOFTWARE\\Wow6432Node\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\Git_is1"
-#endif
-
-typedef struct {
-	git_win32_path path;
-	DWORD len;
-} _findfile_path;
-
-static int git_win32__expand_path(_findfile_path *dest, const wchar_t *src)
+static int git_win32__expand_path(git_win32_path dest, const wchar_t *src)
 {
-	dest->len = ExpandEnvironmentStringsW(src, dest->path, ARRAY_SIZE(dest->path));
+	DWORD len = ExpandEnvironmentStringsW(src, dest, GIT_WIN_PATH_UTF16);
 
-	if (!dest->len || dest->len > ARRAY_SIZE(dest->path))
+	if (!len || len > GIT_WIN_PATH_UTF16)
 		return -1;
 
 	return 0;
@@ -49,111 +39,141 @@ static int win32_path_to_8(git_str *dest, const wchar_t *src)
 	return git_str_sets(dest, utf8_path);
 }
 
-static wchar_t *win32_walkpath(wchar_t *path, wchar_t *buf, size_t buflen)
-{
-	wchar_t term, *base = path;
-
-	GIT_ASSERT_ARG_WITH_RETVAL(path, NULL);
-	GIT_ASSERT_ARG_WITH_RETVAL(buf, NULL);
-	GIT_ASSERT_ARG_WITH_RETVAL(buflen, NULL);
-
-	term = (*path == L'"') ? *path++ : L';';
+static git_win32_path mock_registry;
+static bool mock_registry_set;
 
-	for (buflen--; *path && *path != term && buflen; buflen--)
-		*buf++ = *path++;
-
-	*buf = L'\0'; /* reserved a byte via initial subtract */
+extern int git_win32__set_registry_system_dir(const wchar_t *mock_sysdir)
+{
+	if (!mock_sysdir) {
+		mock_registry[0] = L'\0';
+		mock_registry_set = false;
+	} else {
+		size_t len = wcslen(mock_sysdir);
+
+		if (len > GIT_WIN_PATH_MAX) {
+			git_error_set(GIT_ERROR_INVALID, "mock path too long");
+			return -1;
+		}
 
-	while (*path == term || *path == L';')
-		path++;
+		wcscpy(mock_registry, mock_sysdir);
+		mock_registry_set = true;
+	}
 
-	return (path != base) ? path : NULL;
+	return 0;
 }
 
-static int win32_find_git_in_path(git_str *buf, const wchar_t *gitexe, const wchar_t *subdir)
+static int lookup_registry_key(
+	git_win32_path out,
+	const HKEY hive,
+	const wchar_t* key,
+	const wchar_t *value)
 {
-	wchar_t *env = _wgetenv(L"PATH"), lastch;
-	_findfile_path root;
-	size_t gitexe_len = wcslen(gitexe);
+	HKEY hkey;
+	DWORD type, size;
+	int error = GIT_ENOTFOUND;
 
-	if (!env)
-		return -1;
+	/*
+	 * Registry data may not be NUL terminated, provide room to do
+	 * it ourselves.
+	 */
+	size = (DWORD)((sizeof(git_win32_path) - 1) * sizeof(wchar_t));
+
+	if (RegOpenKeyExW(hive, key, 0, KEY_READ, &hkey) != 0)
+		return GIT_ENOTFOUND;
+
+	if (RegQueryValueExW(hkey, value, NULL, &type, (LPBYTE)out, &size) == 0 &&
+	    type == REG_SZ &&
+	    size > 0 &&
+	    size < sizeof(git_win32_path)) {
+		size_t wsize = size / sizeof(wchar_t);
+		size_t len = wsize - 1;
+
+		if (out[wsize - 1] != L'\0') {
+			len = wsize;
+			out[wsize] = L'\0';
+		}
 
-	while ((env = win32_walkpath(env, root.path, MAX_PATH-1)) && *root.path) {
-		root.len = (DWORD)wcslen(root.path);
-		lastch = root.path[root.len - 1];
+		if (out[len - 1] == L'\\')
+			out[len - 1] = L'\0';
 
-		/* ensure trailing slash (MAX_PATH-1 to walkpath guarantees space) */
-		if (lastch != L'/' && lastch != L'\\') {
-			root.path[root.len++] = L'\\';
-			root.path[root.len]   = L'\0';
-		}
+		if (_waccess(out, F_OK) == 0)
+			error = 0;
+	}
 
-		if (root.len + gitexe_len >= MAX_PATH)
-			continue;
-		wcscpy(&root.path[root.len], gitexe);
+	RegCloseKey(hkey);
+	return error;
+}
 
-		if (_waccess(root.path, F_OK) == 0 && root.len > 5) {
-			/* replace "bin\\" or "cmd\\" with subdir */
-			wcscpy(&root.path[root.len - 4], subdir);
+static int find_sysdir_in_registry(git_win32_path out)
+{
+	if (mock_registry_set) {
+		if (mock_registry[0] == L'\0')
+			return GIT_ENOTFOUND;
 
-			win32_path_to_8(buf, root.path);
-			return 0;
-		}
+		wcscpy(out, mock_registry);
+		return 0;
 	}
 
-	return GIT_ENOTFOUND;
+	if (lookup_registry_key(out, HKEY_CURRENT_USER, REG_GITFORWINDOWS_KEY, L"InstallLocation") == 0 ||
+	    lookup_registry_key(out, HKEY_CURRENT_USER, REG_GITFORWINDOWS_KEY_WOW64, L"InstallLocation") == 0 ||
+	    lookup_registry_key(out, HKEY_LOCAL_MACHINE, REG_GITFORWINDOWS_KEY, L"InstallLocation") == 0 ||
+	    lookup_registry_key(out, HKEY_LOCAL_MACHINE, REG_GITFORWINDOWS_KEY_WOW64, L"InstallLocation") == 0)
+		return 0;
+
+    return GIT_ENOTFOUND;
 }
 
-static int win32_find_git_in_registry(
-	git_str *buf, const HKEY hive, const wchar_t *key, const wchar_t *subdir)
+static int find_sysdir_in_path(git_win32_path out)
 {
-	HKEY hKey;
-	int error = GIT_ENOTFOUND;
+	size_t out_len;
 
-	GIT_ASSERT_ARG(buf);
+	if (git_win32_path_find_executable(out, L"git.exe") < 0 &&
+	    git_win32_path_find_executable(out, L"git.cmd") < 0)
+		return GIT_ENOTFOUND;
 
-	if (!RegOpenKeyExW(hive, key, 0, KEY_READ, &hKey)) {
-		DWORD dwType, cbData;
-		git_win32_path path;
+	out_len = wcslen(out);
 
-		/* Ensure that the buffer is big enough to have the suffix attached
-		 * after we receive the result. */
-		cbData = (DWORD)(sizeof(path) - wcslen(subdir) * sizeof(wchar_t));
+	/* Trim the file name */
+	if (out_len <= CONST_STRLEN(L"git.exe"))
+		return GIT_ENOTFOUND;
 
-		/* InstallLocation points to the root of the git directory */
-		if (!RegQueryValueExW(hKey, L"InstallLocation", NULL, &dwType, (LPBYTE)path, &cbData) &&
-			dwType == REG_SZ) {
+	out_len -= CONST_STRLEN(L"git.exe");
 
-			/* Append the suffix */
-			wcscat(path, subdir);
+	if (out_len && out[out_len - 1] == L'\\')
+		out_len--;
 
-			/* Convert to UTF-8, with forward slashes, and output the path
-			 * to the provided buffer */
-			if (!win32_path_to_8(buf, path))
-				error = 0;
-		}
+	/*
+	 * Git for Windows usually places the command in a 'bin' or
+	 * 'cmd' directory, trim that.
+	 */
+	if (out_len >= CONST_STRLEN(L"\\bin") &&
+	    wcsncmp(&out[out_len - CONST_STRLEN(L"\\bin")], L"\\bin", CONST_STRLEN(L"\\bin")) == 0)
+		out_len -= CONST_STRLEN(L"\\bin");
+	else if (out_len >= CONST_STRLEN(L"\\cmd") &&
+	         wcsncmp(&out[out_len - CONST_STRLEN(L"\\cmd")], L"\\cmd", CONST_STRLEN(L"\\cmd")) == 0)
+		out_len -= CONST_STRLEN(L"\\cmd");
 
-		RegCloseKey(hKey);
-	}
+	if (!out_len)
+		return GIT_ENOTFOUND;
 
-	return error;
+	out[out_len] = L'\0';
+	return 0;
 }
 
 static int win32_find_existing_dirs(
-	git_str *out, const wchar_t *tmpl[])
+    git_str* out,
+    const wchar_t* tmpl[])
 {
-	_findfile_path path16;
+	git_win32_path path16;
 	git_str buf = GIT_STR_INIT;
 
 	git_str_clear(out);
 
 	for (; *tmpl != NULL; tmpl++) {
-		if (!git_win32__expand_path(&path16, *tmpl) &&
-			path16.path[0] != L'%' &&
-			!_waccess(path16.path, F_OK))
-		{
-			win32_path_to_8(&buf, path16.path);
+		if (!git_win32__expand_path(path16, *tmpl) &&
+		    path16[0] != L'%' &&
+		    !_waccess(path16, F_OK)) {
+			win32_path_to_8(&buf, path16);
 
 			if (buf.size)
 				git_str_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, buf.ptr);
@@ -165,31 +185,67 @@ static int win32_find_existing_dirs(
 	return (git_str_oom(out) ? -1 : 0);
 }
 
-int git_win32__find_system_dirs(git_str *out, const wchar_t *subdir)
+static int append_subdir(git_str *out, git_str *path, const char *subdir)
 {
-	git_str buf = GIT_STR_INIT;
+	static const char* architecture_roots[] = {
+		"",
+		"mingw64",
+		"mingw32",
+		NULL
+	};
+	const char **root;
+	size_t orig_path_len = path->size;
 
-	/* directories where git.exe & git.cmd are found */
-	if (!win32_find_git_in_path(&buf, L"git.exe", subdir) && buf.size)
-		git_str_set(out, buf.ptr, buf.size);
-	else
-		git_str_clear(out);
+	for (root = architecture_roots; *root; root++) {
+		if ((*root[0] && git_str_joinpath(path, path->ptr, *root) < 0) ||
+		    git_str_joinpath(path, path->ptr, subdir) < 0)
+			return -1;
 
-	if (!win32_find_git_in_path(&buf, L"git.cmd", subdir) && buf.size)
-		git_str_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, buf.ptr);
+		if (git_fs_path_exists(path->ptr) &&
+		    git_str_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, path->ptr) < 0)
+			return -1;
 
-	/* directories where git is installed according to registry */
-	if (!win32_find_git_in_registry(
-			&buf, HKEY_CURRENT_USER, REG_MSYSGIT_INSTALL_LOCAL, subdir) && buf.size)
-		git_str_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, buf.ptr);
+		git_str_truncate(path, orig_path_len);
+	}
 
-	if (!win32_find_git_in_registry(
-			&buf, HKEY_LOCAL_MACHINE, REG_MSYSGIT_INSTALL, subdir) && buf.size)
-		git_str_join(out, GIT_PATH_LIST_SEPARATOR, out->ptr, buf.ptr);
+	return 0;
+}
 
-	git_str_dispose(&buf);
+int git_win32__find_system_dirs(git_str *out, const char *subdir)
+{
+	git_win32_path pathdir, regdir;
+	git_str path8 = GIT_STR_INIT;
+	bool has_pathdir, has_regdir;
+	int error;
+
+	has_pathdir = (find_sysdir_in_path(pathdir) == 0);
+	has_regdir = (find_sysdir_in_registry(regdir) == 0);
+
+	if (!has_pathdir && !has_regdir)
+		return GIT_ENOTFOUND;
+
+	/*
+	 * Usually the git in the path is the same git in the registry,
+	 * in this case there's no need to duplicate the paths.
+	 */
+	if (has_pathdir && has_regdir && wcscmp(pathdir, regdir) == 0)
+		has_regdir = false;
+
+	if (has_pathdir) {
+		if ((error = win32_path_to_8(&path8, pathdir)) < 0 ||
+		    (error = append_subdir(out, &path8, subdir)) < 0)
+			goto done;
+	}
 
-	return (git_str_oom(out) ? -1 : 0);
+	if (has_regdir) {
+		if ((error = win32_path_to_8(&path8, regdir)) < 0 ||
+		    (error = append_subdir(out, &path8, subdir)) < 0)
+			goto done;
+	}
+
+done:
+    git_str_dispose(&path8);
+    return error;
 }
 
 int git_win32__find_global_dirs(git_str *out)
diff --git a/src/win32/findfile.h b/src/win32/findfile.h
index e11cceb..61fb7db 100644
--- a/src/win32/findfile.h
+++ b/src/win32/findfile.h
@@ -10,7 +10,10 @@
 
 #include "common.h"
 
-extern int git_win32__find_system_dirs(git_str *out, const wchar_t *subpath);
+/** Sets the mock registry root for Git for Windows for testing. */
+extern int git_win32__set_registry_system_dir(const wchar_t *mock_sysdir);
+
+extern int git_win32__find_system_dirs(git_str *out, const char *subpath);
 extern int git_win32__find_global_dirs(git_str *out);
 extern int git_win32__find_xdg_dirs(git_str *out);
 extern int git_win32__find_programdata_dirs(git_str *out);
diff --git a/src/win32/path_w32.c b/src/win32/path_w32.c
index 0e6aff7..d9fc829 100644
--- a/src/win32/path_w32.c
+++ b/src/win32/path_w32.c
@@ -151,6 +151,137 @@ int git_win32_path_canonicalize(git_win32_path path)
 	return (int)(to - path);
 }
 
+static int git_win32_path_join(
+	git_win32_path dest,
+	const wchar_t *one,
+	size_t one_len,
+	const wchar_t *two,
+	size_t two_len)
+{
+	size_t backslash = 0;
+
+	if (one_len && two_len && one[one_len - 1] != L'\\')
+		backslash = 1;
+
+	if (one_len + two_len + backslash > MAX_PATH) {
+		git_error_set(GIT_ERROR_INVALID, "path too long");
+		return -1;
+	}
+
+	memmove(dest, one, one_len * sizeof(wchar_t));
+
+	if (backslash)
+		dest[one_len] = L'\\';
+
+	memcpy(dest + one_len + backslash, two, two_len * sizeof(wchar_t));
+	dest[one_len + backslash + two_len] = L'\0';
+
+	return 0;
+}
+
+struct win32_path_iter {
+	wchar_t *env;
+	const wchar_t *current_dir;
+};
+
+static int win32_path_iter_init(struct win32_path_iter *iter)
+{
+	DWORD len = GetEnvironmentVariableW(L"PATH", NULL, 0);
+
+	if (!len && GetLastError() == ERROR_ENVVAR_NOT_FOUND) {
+		iter->env = NULL;
+		iter->current_dir = NULL;
+		return 0;
+	} else if (!len) {
+		git_error_set(GIT_ERROR_OS, "could not load PATH");
+		return -1;
+	}
+
+	iter->env = git__malloc(len * sizeof(wchar_t));
+	GIT_ERROR_CHECK_ALLOC(iter->env);
+
+	len = GetEnvironmentVariableW(L"PATH", iter->env, len);
+
+	if (len == 0) {
+		git_error_set(GIT_ERROR_OS, "could not load PATH");
+		return -1;
+	}
+
+	iter->current_dir = iter->env;
+	return 0;
+}
+
+static int win32_path_iter_next(
+	const wchar_t **out,
+	size_t *out_len,
+	struct win32_path_iter *iter)
+{
+	const wchar_t *start;
+	wchar_t term;
+	size_t len = 0;
+
+	if (!iter->current_dir || !*iter->current_dir)
+		return GIT_ITEROVER;
+
+	term = (*iter->current_dir == L'"') ? *iter->current_dir++ : L';';
+	start = iter->current_dir;
+
+	while (*iter->current_dir && *iter->current_dir != term) {
+		iter->current_dir++;
+		len++;
+	}
+
+	*out = start;
+	*out_len = len;
+
+	if (term == L'"' && *iter->current_dir)
+		iter->current_dir++;
+
+	while (*iter->current_dir == L';')
+		iter->current_dir++;
+
+	return 0;
+}
+
+static void win32_path_iter_dispose(struct win32_path_iter *iter)
+{
+	if (!iter)
+		return;
+
+	git__free(iter->env);
+	iter->env = NULL;
+	iter->current_dir = NULL;
+}
+
+int git_win32_path_find_executable(git_win32_path fullpath, wchar_t *exe)
+{
+	struct win32_path_iter path_iter;
+	const wchar_t *dir;
+	size_t dir_len, exe_len = wcslen(exe);
+	bool found = false;
+
+	if (win32_path_iter_init(&path_iter) < 0)
+		return -1;
+
+	while (win32_path_iter_next(&dir, &dir_len, &path_iter) != GIT_ITEROVER) {
+		if (git_win32_path_join(fullpath, dir, dir_len, exe, exe_len) < 0)
+			continue;
+
+		if (_waccess(fullpath, 0) == 0) {
+			found = true;
+			break;
+		}
+	}
+
+	win32_path_iter_dispose(&path_iter);
+
+	if (found)
+		return 0;
+
+	fullpath[0] = L'\0';
+	return GIT_ENOTFOUND;
+}
+
 static int win32_path_cwd(wchar_t *out, size_t len)
 {
 	int cwd_len;
diff --git a/src/win32/path_w32.h b/src/win32/path_w32.h
index 4fadf8d..837b11e 100644
--- a/src/win32/path_w32.h
+++ b/src/win32/path_w32.h
@@ -86,4 +86,6 @@ size_t git_win32_path_trim_end(wchar_t *str, size_t len);
  */
 size_t git_win32_path_remove_namespace(wchar_t *str, size_t len);
 
+int git_win32_path_find_executable(git_win32_path fullpath, wchar_t* exe);
+
 #endif
diff --git a/tests/core/path.c b/tests/core/path.c
index 563dcd2..a0ae77f 100644
--- a/tests/core/path.c
+++ b/tests/core/path.c
@@ -2,6 +2,20 @@
 #include "futils.h"
 #include "fs_path.h"
 
+static char *path_save;
+
+void test_core_path__initialize(void)
+{
+	path_save = cl_getenv("PATH");
+}
+
+void test_core_path__cleanup(void)
+{
+	cl_setenv("PATH", path_save);
+	git__free(path_save);
+	path_save = NULL;
+}
+
 static void
 check_dirname(const char *A, const char *B)
 {
@@ -60,6 +74,20 @@ check_joinpath_n(
 	git_str_dispose(&joined_path);
 }
 
+static void check_setenv(const char* name, const char* value)
+{
+    char* check;
+
+    cl_git_pass(cl_setenv(name, value));
+    check = cl_getenv(name);
+
+    if (value)
+	cl_assert_equal_s(value, check);
+    else
+	cl_assert(check == NULL);
+
+    git__free(check);
+}
 
 /* get the dirname of a path */
 void test_core_path__00_dirname(void)
@@ -651,3 +679,61 @@ void test_core_path__16_resolve_relative(void)
 	assert_common_dirlen(6, "a/b/c/foo.txt", "a/b/c/d/e/bar.txt");
 	assert_common_dirlen(7, "/a/b/c/foo.txt", "/a/b/c/d/e/bar.txt");
 }
+
+static void fix_path(git_str *s)
+{
+#ifndef GIT_WIN32
+	GIT_UNUSED(s);
+#else
+	char* c;
+
+	for (c = s->ptr; *c; c++) {
+		if (*c == '/')
+			*c = '\\';
+	}
+#endif
+}
+
+void test_core_path__find_exe_in_path(void)
+{
+	char *orig_path;
+	git_str sandbox_path = GIT_STR_INIT;
+	git_str new_path = GIT_STR_INIT, full_path = GIT_STR_INIT,
+	        dummy_path = GIT_STR_INIT;
+
+#ifdef GIT_WIN32
+	static const char *bogus_path_1 = "c:\\does\\not\\exist\\";
+	static const char *bogus_path_2 = "e:\\non\\existent";
+#else
+	static const char *bogus_path_1 = "/this/path/does/not/exist/";
+	static const char *bogus_path_2 = "/non/existent";
+#endif
+
+	orig_path = cl_getenv("PATH");
+
+	git_str_puts(&sandbox_path, clar_sandbox_path());
+	git_str_joinpath(&dummy_path, sandbox_path.ptr, "dummmmmmmy_libgit2_file");
+	cl_git_rewritefile(dummy_path.ptr, "this is a dummy file");
+
+	fix_path(&sandbox_path);
+	fix_path(&dummy_path);
+
+	cl_git_pass(git_str_printf(&new_path, "%s%c%s%c%s%c%s",
+		bogus_path_1, GIT_PATH_LIST_SEPARATOR,
+		orig_path, GIT_PATH_LIST_SEPARATOR,
+		sandbox_path.ptr, GIT_PATH_LIST_SEPARATOR,
+		bogus_path_2));
+
+	check_setenv("PATH", new_path.ptr);
+
+	cl_git_fail_with(GIT_ENOTFOUND, git_fs_path_find_executable(&full_path, "this_file_does_not_exist"));
+	cl_git_pass(git_fs_path_find_executable(&full_path, "dummmmmmmy_libgit2_file"));
+
+	cl_assert_equal_s(full_path.ptr, dummy_path.ptr);
+
+	git_str_dispose(&full_path);
+	git_str_dispose(&new_path);
+	git_str_dispose(&dummy_path);
+	git_str_dispose(&sandbox_path);
+	git__free(orig_path);
+}
diff --git a/tests/win32/systemdir.c b/tests/win32/systemdir.c
new file mode 100644
index 0000000..46fa06a
--- /dev/null
+++ b/tests/win32/systemdir.c
@@ -0,0 +1,328 @@
+#include "clar_libgit2.h"
+#include "futils.h"
+#include "sysdir.h"
+#include "win32/findfile.h"
+
+#ifdef GIT_WIN32
+static char *path_save;
+static git_str gfw_path_root = GIT_STR_INIT;
+static git_str gfw_registry_root = GIT_STR_INIT;
+#endif
+
+void test_win32_systemdir__initialize(void)
+{
+#ifdef GIT_WIN32
+	git_str path_env = GIT_STR_INIT;
+
+	path_save = cl_getenv("PATH");
+	git_win32__set_registry_system_dir(L"");
+
+	cl_git_pass(git_str_puts(&path_env, "C:\\GitTempTest\\Foo;\"c:\\program files\\doesnotexisttesttemp\";C:\\fakefakedoesnotexist"));
+	cl_setenv("PATH", path_env.ptr);
+
+	cl_git_pass(git_str_puts(&gfw_path_root, clar_sandbox_path()));
+	cl_git_pass(git_str_puts(&gfw_path_root, "/fake_gfw_path_install"));
+
+	cl_git_pass(git_str_puts(&gfw_registry_root, clar_sandbox_path()));
+	cl_git_pass(git_str_puts(&gfw_registry_root, "/fake_gfw_registry_install"));
+
+	git_str_dispose(&path_env);
+#endif
+}
+
+void test_win32_systemdir__cleanup(void)
+{
+#ifdef GIT_WIN32
+	cl_fixture_cleanup("fake_gfw_path_install");
+	cl_fixture_cleanup("fake_gfw_registry_install");
+	git_str_dispose(&gfw_path_root);
+	git_str_dispose(&gfw_registry_root);
+
+	cl_setenv("PATH", path_save);
+	git__free(path_save);
+	path_save = NULL;
+
+	git_win32__set_registry_system_dir(NULL);
+	cl_sandbox_set_search_path_defaults();
+#endif
+}
+
+#ifdef GIT_WIN32
+static void fix_path(git_str *s)
+{
+	char *c;
+
+	for (c = s->ptr; *c; c++) {
+		if (*c == '/')
+			*c = '\\';
+	}
+}
+
+static void populate_fake_gfw(
+	git_str *expected_etc_dir,
+	const char *root,
+	const char *token,
+	bool create_gitconfig,
+	bool create_mingw64_gitconfig,
+	bool add_to_path,
+	bool add_to_registry)
+{
+	git_str bin_path = GIT_STR_INIT, exe_path = GIT_STR_INIT,
+	etc_path = GIT_STR_INIT, mingw64_path = GIT_STR_INIT,
+	config_path = GIT_STR_INIT, path_env = GIT_STR_INIT,
+	config_data = GIT_STR_INIT;
+
+	cl_git_pass(git_str_puts(&bin_path, root));
+	cl_git_pass(git_str_puts(&bin_path, "/cmd"));
+	cl_git_pass(git_futils_mkdir_r(bin_path.ptr, 0755));
+
+	cl_git_pass(git_str_puts(&exe_path, bin_path.ptr));
+	cl_git_pass(git_str_puts(&exe_path, "/git.cmd"));
+	cl_git_mkfile(exe_path.ptr, "This is a fake executable.");
+
+	cl_git_pass(git_str_puts(&etc_path, root));
+	cl_git_pass(git_str_puts(&etc_path, "/etc"));
+	cl_git_pass(git_futils_mkdir_r(etc_path.ptr, 0755));
+
+	cl_git_pass(git_str_puts(&mingw64_path, root));
+	cl_git_pass(git_str_puts(&mingw64_path, "/mingw64/etc"));
+	cl_git_pass(git_futils_mkdir_r(mingw64_path.ptr, 0755));
+
+	if (create_gitconfig) {
+		git_str_clear(&config_data);
+		git_str_printf(&config_data, "[gfw]\n\ttest = etc %s\n", token);
+
+		cl_git_pass(git_str_puts(&config_path, etc_path.ptr));
+		cl_git_pass(git_str_puts(&config_path, "/gitconfig"));
+		cl_git_mkfile(config_path.ptr, config_data.ptr);
+	}
+
+	if (create_mingw64_gitconfig) {
+		git_str_clear(&config_data);
+		git_str_printf(&config_data, "[gfw]\n\ttest = mingw64 %s\n", token);
+
+		git_str_clear(&config_path);
+		cl_git_pass(git_str_puts(&config_path, mingw64_path.ptr));
+		cl_git_pass(git_str_puts(&config_path, "/gitconfig"));
+		cl_git_mkfile(config_path.ptr, config_data.ptr);
+	}
+
+	if (add_to_path) {
+		fix_path(&bin_path);
+		cl_git_pass(git_str_puts(&path_env, "C:\\GitTempTest\\Foo;\"c:\\program files\\doesnotexisttesttemp\";"));
+		cl_git_pass(git_str_puts(&path_env, bin_path.ptr));
+		cl_git_pass(git_str_puts(&path_env, ";C:\\fakefakedoesnotexist"));
+		cl_setenv("PATH", path_env.ptr);
+	}
+
+	if (add_to_registry) {
+		git_win32_path registry_path;
+		size_t offset = 0;
+
+		cl_assert(git_win32_path_from_utf8(registry_path, root) >= 0);
+		if (wcsncmp(registry_path, L"\\\\?\\", CONST_STRLEN("\\\\?\\")) == 0)
+		    offset = CONST_STRLEN("\\\\?\\");
+		git_win32__set_registry_system_dir(registry_path + offset);
+	}
+
+	cl_git_pass(git_str_join(expected_etc_dir, GIT_PATH_LIST_SEPARATOR, expected_etc_dir->ptr, etc_path.ptr));
+	cl_git_pass(git_str_join(expected_etc_dir, GIT_PATH_LIST_SEPARATOR, expected_etc_dir->ptr, mingw64_path.ptr));
+
+	git_str_dispose(&bin_path);
+	git_str_dispose(&exe_path);
+	git_str_dispose(&etc_path);
+	git_str_dispose(&mingw64_path);
+	git_str_dispose(&config_path);
+	git_str_dispose(&path_env);
+	git_str_dispose(&config_data);
+}
+
+static void populate_fake_ecosystem(
+	git_str *expected_etc_dir,
+	bool create_gitconfig,
+	bool create_mingw64_gitconfig,
+	bool path,
+	bool registry)
+{
+	if (path)
+		populate_fake_gfw(expected_etc_dir, gfw_path_root.ptr, "path", create_gitconfig, create_mingw64_gitconfig, true, false);
+
+	if (registry)
+		populate_fake_gfw(expected_etc_dir, gfw_registry_root.ptr, "registry", create_gitconfig, create_mingw64_gitconfig, false, true);
+}
+#endif
+
+void test_win32_systemdir__finds_etc_in_path(void)
+{
+#ifdef GIT_WIN32
+	git_str expected = GIT_STR_INIT, out = GIT_STR_INIT;
+	git_config *cfg;
+	git_buf value = GIT_BUF_INIT;
+
+	populate_fake_ecosystem(&expected, true, false, true, false);
+
+	cl_git_pass(git_win32__find_system_dirs(&out, "etc"));
+	cl_assert_equal_s(out.ptr, expected.ptr);
+
+	git_sysdir_reset();
+
+	cl_git_pass(git_config_open_default(&cfg));
+	cl_git_pass(git_config_get_string_buf(&value, cfg, "gfw.test"));
+	cl_assert_equal_s("etc path", value.ptr);
+
+	git_buf_dispose(&value);
+	git_str_dispose(&expected);
+	git_str_dispose(&out);
+	git_config_free(cfg);
+#endif
+}
+
+void test_win32_systemdir__finds_mingw64_etc_in_path(void)
+{
+#ifdef GIT_WIN32
+	git_str expected = GIT_STR_INIT, out = GIT_STR_INIT;
+	git_config* cfg;
+	git_buf value = GIT_BUF_INIT;
+
+	populate_fake_ecosystem(&expected, false, true, true, false);
+
+	cl_git_pass(git_win32__find_system_dirs(&out, "etc"));
+	cl_assert_equal_s(out.ptr, expected.ptr);
+
+	git_sysdir_reset();
+
+	cl_git_pass(git_config_open_default(&cfg));
+	cl_git_pass(git_config_get_string_buf(&value, cfg, "gfw.test"));
+	cl_assert_equal_s("mingw64 path", value.ptr);
+
+	git_buf_dispose(&value);
+	git_str_dispose(&expected);
+	git_str_dispose(&out);
+	git_config_free(cfg);
+#endif
+}
+
+void test_win32_systemdir__prefers_etc_to_mingw64_in_path(void)
+{
+#ifdef GIT_WIN32
+	git_str expected = GIT_STR_INIT, out = GIT_STR_INIT;
+	git_config* cfg;
+	git_buf value = GIT_BUF_INIT;
+
+	populate_fake_ecosystem(&expected, true, true, true, false);
+
+	cl_git_pass(git_win32__find_system_dirs(&out, "etc"));
+	cl_assert_equal_s(out.ptr, expected.ptr);
+
+	git_sysdir_reset();
+
+	cl_git_pass(git_config_open_default(&cfg));
+	cl_git_pass(git_config_get_string_buf(&value, cfg, "gfw.test"));
+	cl_assert_equal_s("etc path", value.ptr);
+
+	git_buf_dispose(&value);
+	git_str_dispose(&expected);
+	git_str_dispose(&out);
+	git_config_free(cfg);
+#endif
+}
+
+void test_win32_systemdir__finds_etc_in_registry(void)
+{
+#ifdef GIT_WIN32
+	git_str expected = GIT_STR_INIT, out = GIT_STR_INIT;
+	git_config* cfg;
+	git_buf value = GIT_BUF_INIT;
+
+	populate_fake_ecosystem(&expected, true, false, false, true);
+
+	cl_git_pass(git_win32__find_system_dirs(&out, "etc"));
+	cl_assert_equal_s(out.ptr, expected.ptr);
+
+	git_sysdir_reset();
+
+	cl_git_pass(git_config_open_default(&cfg));
+	cl_git_pass(git_config_get_string_buf(&value, cfg, "gfw.test"));
+	cl_assert_equal_s("etc registry", value.ptr);
+
+	git_buf_dispose(&value);
+	git_str_dispose(&expected);
+	git_str_dispose(&out);
+	git_config_free(cfg);
+#endif
+}
+
+void test_win32_systemdir__finds_mingw64_etc_in_registry(void)
+{
+#ifdef GIT_WIN32
+	git_str expected = GIT_STR_INIT, out = GIT_STR_INIT;
+	git_config* cfg;
+	git_buf value = GIT_BUF_INIT;
+
+	populate_fake_ecosystem(&expected, false, true, false, true);
+
+	cl_git_pass(git_win32__find_system_dirs(&out, "etc"));
+	cl_assert_equal_s(out.ptr, expected.ptr);
+
+	git_sysdir_reset();
+
+	cl_git_pass(git_config_open_default(&cfg));
+	cl_git_pass(git_config_get_string_buf(&value, cfg, "gfw.test"));
+	cl_assert_equal_s("mingw64 registry", value.ptr);
+
+	git_buf_dispose(&value);
+	git_str_dispose(&expected);
+	git_str_dispose(&out);
+	git_config_free(cfg);
+#endif
+}
+
+void test_win32_systemdir__prefers_etc_to_mingw64_in_registry(void)
+{
+#ifdef GIT_WIN32
+	git_str expected = GIT_STR_INIT, out = GIT_STR_INIT;
+	git_config* cfg;
+	git_buf value = GIT_BUF_INIT;
+
+	populate_fake_ecosystem(&expected, true, true, false, true);
+
+	cl_git_pass(git_win32__find_system_dirs(&out, "etc"));
+	cl_assert_equal_s(out.ptr, expected.ptr);
+
+	git_sysdir_reset();
+
+	cl_git_pass(git_config_open_default(&cfg));
+	cl_git_pass(git_config_get_string_buf(&value, cfg, "gfw.test"));
+	cl_assert_equal_s("etc registry", value.ptr);
+
+	git_buf_dispose(&value);
+	git_str_dispose(&expected);
+	git_str_dispose(&out);
+	git_config_free(cfg);
+#endif
+}
+
+void test_win32_systemdir__prefers_path_to_registry(void)
+{
+#ifdef GIT_WIN32
+	git_str expected = GIT_STR_INIT, out = GIT_STR_INIT;
+	git_config* cfg;
+	git_buf value = GIT_BUF_INIT;
+
+	populate_fake_ecosystem(&expected, true, true, true, true);
+
+	cl_git_pass(git_win32__find_system_dirs(&out, "etc"));
+	cl_assert_equal_s(out.ptr, expected.ptr);
+
+	git_sysdir_reset();
+
+	cl_git_pass(git_config_open_default(&cfg));
+	cl_git_pass(git_config_get_string_buf(&value, cfg, "gfw.test"));
+	cl_assert_equal_s("etc path", value.ptr);
+
+	git_buf_dispose(&value);
+	git_str_dispose(&expected);
+	git_str_dispose(&out);
+	git_config_free(cfg);
+#endif
+}