Add tests to urlx, corx, cmdx

Signed-off-by: aeneasr <aeneas.rekkas@serlo.org>

cmdx/env_test.go

@@ -0,0 +1,10 @@
+package cmdx
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestEnvVarExamplesHelpMessage(t *testing.T) {
+	assert.NotEmpty(t, EnvVarExamplesHelpMessage(""))
+}

corsx/corsx_test.go

@@ -1 +1,10 @@
 package corsx
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestHelpMessage(t *testing.T) {
+	assert.NotEmpty(t, HelpMessage())
+}

urlx/join_test.go

@@ -0,0 +1,10 @@
+package urlx
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestJoin(t *testing.T) {
+	assert.EqualValues(t, "http://foo/bar/baz/bar", MustJoin("http://foo", "bar/", "/baz", "bar"))
+}