Add some tests

Makefile

@@ -6,7 +6,10 @@ clean:
 	rm -f -- $(TARGET)
 
 fmt:
-	gofmt -tabs=false -tabwidth=4 -w=true $(TARGET).go
+	gofmt -tabs=false -tabwidth=4 -w=true *.go
 
 install:
 	go build $(TARGET).go
+
+test:
+	go test

ifconfig_test.go

@@ -0,0 +1,21 @@
+package main
+
+import "testing"
+
+func TestIsCLi(t *testing.T) {
+    userAgents := []string{"curl/7.26.0", "Wget/1.13.4 (linux-gnu)",
+        "fetch libfetch/2.0"}
+
+    for _, userAgent := range userAgents {
+        if !isCli(userAgent) {
+            t.Errorf("Expected true for %s", userAgent)
+        }
+    }
+
+    browserUserAgent := "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_4) " +
+        "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/30.0.1599.28 " +
+        "Safari/537.36"
+    if isCli(browserUserAgent) {
+        t.Errorf("Expected false for %s", browserUserAgent)
+    }
+}