Update 'go-cheatsheet.md'

go-cheatsheet.md

@@ -2,6 +2,26 @@
 
 ## testing
 
+### use testify
+
+```
+import "github.com/stretchr/testify/assert"
+
+
+func TestSomething(t *testing.T) {
+	a := assert.New(t)
+
+    thing, err := functionCall()
+    
+	t.Logf("%#v", thing)
+
+	a.NotNil(err)
+}
+```
+
+
+### use %#v
+
 ``` go
 t.Logf("%#v", eim)
 ```