Fixing Windows tests

io_posix.c

@@ -86,6 +86,7 @@ bool ethash_file_size(FILE* f, size_t* ret_size)
 
 bool ethash_get_default_dirname(char* strbuf, size_t buffsize)
 {
+	static const char dir_suffix[] = ".ethash/";
 	strbuf[0] = '\0';
 	char* home_dir = getenv("HOME");
 	size_t len = strlen(home_dir);
@@ -97,5 +98,5 @@ bool ethash_get_default_dirname(char* strbuf, size_t buffsize)
 			return false;
 		}
 	}
-	return ethash_strncat(strbuf, buffsize, ".ethash/", 8);
+	return ethash_strncat(strbuf, buffsize, dir_suffix, sizeof(dir_suffix));
 }

io_win32.c

@@ -87,6 +87,7 @@ bool ethash_file_size(FILE* f, size_t* ret_size)
 
 bool ethash_get_default_dirname(char* strbuf, size_t buffsize)
 {
+	static const char dir_suffix[] = "Appdata\\Ethash\\";
 	strbuf[0] = '\0';
 	if (!SUCCEEDED(SHGetFolderPathW(NULL, CSIDL_PROFILE, NULL, 0, (WCHAR*)strbuf))) {
 		return false;
@@ -95,5 +96,5 @@ bool ethash_get_default_dirname(char* strbuf, size_t buffsize)
 		return false;
 	}
 
-	return ethash_strncat(strbuf, buffsize, "Appdata\\Ethash\\", 14);
+	return ethash_strncat(strbuf, buffsize, dir_suffix, sizeof(dir_suffix));
 }