diff --git a/file_checker_test.go b/file_checker_test.go
index 21bf18b..e761123 100644
--- a/file_checker_test.go
+++ b/file_checker_test.go
@@ -85,6 +85,44 @@ func TestFileCheckerExtractURLs(t *testing.T) {
 	}
 }
 
+func TestFileCheckerResolveURL(t *testing.T) {
+	f := newFileChecker(0, "", newSemaphore(1024))
+
+	for _, c := range []struct{ source, target string }{
+		{"foo", "foo"},
+		{"https://google.com", "https://google.com"},
+	} {
+		u, err := f.resolveURL(c.source)
+
+		assert.Equal(t, nil, err)
+		assert.Equal(t, c.target, u)
+	}
+}
+
+func TestFileCheckerResolveURLWithAbsolutePath(t *testing.T) {
+	f := newFileChecker(0, "", newSemaphore(1024))
+
+	u, err := f.resolveURL("/foo")
+
+	assert.NotEqual(t, nil, err)
+	assert.Equal(t, "", u)
+}
+
+func TestFileCheckerResolveURLWithDocumentRoot(t *testing.T) {
+	f := newFileChecker(0, "foo", newSemaphore(1024))
+
+	for _, c := range []struct{ source, target string }{
+		{"foo", "foo"},
+		{"https://google.com", "https://google.com"},
+		{"/foo", "foo/foo"},
+	} {
+		u, err := f.resolveURL(c.source)
+
+		assert.Equal(t, nil, err)
+		assert.Equal(t, c.target, u)
+	}
+}
+
 func TestURLParse(t *testing.T) {
 	u, err := url.Parse("file-path")