add Path::exists()

test/src/test_Path.cc

@@ -38,3 +38,9 @@ TEST(PathTest, dirname)
     EXPECT_EQ(".", Path("folder//").dirname().to_s());
     EXPECT_EQ("a", Path("a/b").dirname().to_s());
 }
+
+TEST(PathTest, exists)
+{
+    EXPECT_TRUE(Path("runtime").exists());
+    EXPECT_FALSE(Path("foobar").exists());
+}