Move git and url checks into pkg

This moves the IsGIT and IsURL functions out of the generic `utils`
package and into their own `urlutil` pkg.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

urlutil/git_test.go

@@ -0,0 +1,43 @@
+package urlutil
+
+import "testing"
+
+var (
+	gitUrls = []string{
+		"git://github.com/docker/docker",
+		"git@github.com:docker/docker.git",
+		"git@bitbucket.org:atlassianlabs/atlassian-docker.git",
+		"https://github.com/docker/docker.git",
+		"http://github.com/docker/docker.git",
+	}
+	incompleteGitUrls = []string{
+		"github.com/docker/docker",
+	}
+)
+
+func TestValidGitTransport(t *testing.T) {
+	for _, url := range gitUrls {
+		if IsGitTransport(url) == false {
+			t.Fatalf("%q should be detected as valid Git prefix", url)
+		}
+	}
+
+	for _, url := range incompleteGitUrls {
+		if IsGitTransport(url) == true {
+			t.Fatalf("%q should not be detected as valid Git prefix", url)
+		}
+	}
+}
+
+func TestIsGIT(t *testing.T) {
+	for _, url := range gitUrls {
+		if IsGitURL(url) == false {
+			t.Fatalf("%q should be detected as valid Git url", url)
+		}
+	}
+	for _, url := range incompleteGitUrls {
+		if IsGitURL(url) == false {
+			t.Fatalf("%q should be detected as valid Git url", url)
+		}
+	}
+}