[lectures/04-testing] Add coverage and t.Cleanup() examples.

lectures/04-testing/gomock/example_test.go

@@ -3,14 +3,13 @@ package example
 import (
 	"testing"
 
-	gomock "github.com/golang/mock/gomock"
+	"github.com/golang/mock/gomock"
 )
 
 func TestFoo(t *testing.T) {
 	ctrl := gomock.NewController(t)
 
-	// Assert that Bar() is invoked.
-	defer ctrl.Finish()
+	defer ctrl.Finish() // Assert that Bar() is invoked.
 
 	m := NewMockFoo(ctrl)
 

lectures/04-testing/lecture.slide

@@ -276,7 +276,23 @@ Good example
 
 * Coverage
 
-- Пример в goland.
+.play size/size.go /func/,/^}/
+
+* Coverage
+
+.play size/size_test.go /func/,/^}/
+
+  go test -cover
+  PASS
+  coverage: 42.9% of statements
+  ok  	gitlab.com/slon/shad-go/lectures/04-testing/size	0.001s
+
+* Coverage
+
+  go test -coverprofile=coverage.out
+  go tool cover -html=coverage.out
+
+.image size/coverage.png
 
 * Benchmark Functions
 
@@ -435,6 +451,20 @@ Good example
       // ...
   }
 
+* t.Cleanup()
+
+  func newEnv(t *testing.T) *env {
+      // ...
+      t.Cleanup(func() {
+          DB.Close()
+      })
+  }
+
+  func TestA(t *testing.T) {
+      env := newEnv(t)
+      // ...
+  }
+
 * Fixture Composition
 
   type MyFixture struct {
@@ -480,7 +510,7 @@ Good example
 
 * White box testing
 
-.play mocks/mocks.go /var/,/OMIT/
+.play mocks/mocks.go /func CheckQuota/,/OMIT/
 
 * White box testing
 

lectures/04-testing/mocks/mocks.go

@@ -13,17 +13,6 @@ func bytesInUse(username string) int {
 	return 10000000000
 }
 
-var notifyUser = doNotifyUser
-
-func doNotifyUser(username, msg string) {
-	auth := smtp.PlainAuth("", sender, password, hostname)
-	err := smtp.SendMail(hostname+":587", auth, sender,
-		[]string{username}, []byte(msg))
-	if err != nil {
-		log.Printf("smtp.SendEmail(%s) failed: %s", username, err)
-	}
-}
-
 func CheckQuota(username string) {
 	used := bytesInUse(username)
 	const quota = 1000000000 // 1GB
@@ -35,4 +24,15 @@ func CheckQuota(username string) {
 	notifyUser(username, msg)
 }
 
+var notifyUser = doNotifyUser
+
+func doNotifyUser(username, msg string) {
+	auth := smtp.PlainAuth("", sender, password, hostname)
+	err := smtp.SendMail(hostname+":587", auth, sender,
+		[]string{username}, []byte(msg))
+	if err != nil {
+		log.Printf("smtp.SendEmail(%s) failed: %s", username, err)
+	}
+}
+
 // OMIT

lectures/04-testing/size/size.go

@@ -0,0 +1,17 @@
+package size
+
+func Size(a int) string {
+	switch {
+	case a < 0:
+		return "negative"
+	case a == 0:
+		return "zero"
+	case a < 10:
+		return "small"
+	case a < 100:
+		return "big"
+	case a < 1000:
+		return "huge"
+	}
+	return "enormous"
+}

lectures/04-testing/size/size_test.go

@@ -0,0 +1,22 @@
+package size
+
+import "testing"
+
+func TestSize(t *testing.T) {
+	type Test struct {
+		in  int
+		out string
+	}
+
+	var tests = []Test{
+		{-1, "negative"},
+		{5, "small"},
+	}
+
+	for i, test := range tests {
+		size := Size(test.in)
+		if size != test.out {
+			t.Errorf("#%d: Size(%d)=%s; want %s", i, test.in, size, test.out)
+		}
+	}
+}