switched to using TB for helpers

arrays-and-slices.md

@@ -503,7 +503,7 @@ Our tests have some repeated code around assertion again, let's extract that int
 ```go
 func TestSumAllTails(t *testing.T) {
 
-	checkSums := func(t *testing.T, got, want []int) {
+	checkSums := func(t testing.TB, got, want []int) {
 		t.Helper()
 		if !reflect.DeepEqual(got, want) {
 			t.Errorf("got %v want %v", got, want)

command-line.md

@@ -261,7 +261,7 @@ The test passes. We'll add another test to force us to write some real code next
 In `server_test` we earlier did checks to see if wins are recorded as we have here. Let's DRY that assertion up into a helper
 
 ```go
-func assertPlayerWin(t *testing.T, store *StubPlayerStore, winner string) {
+func assertPlayerWin(t testing.TB, store *StubPlayerStore, winner string) {
 	t.Helper()
 
 	if len(store.winCalls) != 1 {
@@ -472,7 +472,7 @@ func (s *StubPlayerStore) GetLeague() League {
 	return s.league
 }
 
-func AssertPlayerWin(t *testing.T, store *StubPlayerStore, winner string) {
+func AssertPlayerWin(t testing.TB, store *StubPlayerStore, winner string) {
 	t.Helper()
 
 	if len(store.winCalls) != 1 {

command-line/v1/file_system_store_test.go

@@ -6,7 +6,7 @@ import (
 	"testing"
 )
 
-func createTempFile(t *testing.T, initialData string) (*os.File, func()) {
+func createTempFile(t testing.TB, initialData string) (*os.File, func()) {
 	t.Helper()
 
 	tmpfile, err := ioutil.TempFile("", "db")
@@ -109,14 +109,14 @@ func TestFileSystemStore(t *testing.T) {
 	})
 }
 
-func assertScoreEquals(t *testing.T, got, want int) {
+func assertScoreEquals(t testing.TB, got, want int) {
 	t.Helper()
 	if got != want {
 		t.Errorf("got %d want %d", got, want)
 	}
 }
 
-func assertNoError(t *testing.T, err error) {
+func assertNoError(t testing.TB, err error) {
 	t.Helper()
 	if err != nil {
 		t.Fatalf("didn't expect an error but got one, %v", err)

command-line/v1/server_test.go

@@ -123,14 +123,14 @@ func TestLeague(t *testing.T) {
 	})
 }
 
-func assertContentType(t *testing.T, response *httptest.ResponseRecorder, want string) {
+func assertContentType(t testing.TB, response *httptest.ResponseRecorder, want string) {
 	t.Helper()
 	if response.Header().Get("content-type") != want {
 		t.Errorf("response did not have content-type of %s, got %v", want, response.HeaderMap)
 	}
 }
 
-func getLeagueFromResponse(t *testing.T, body io.Reader) []Player {
+func getLeagueFromResponse(t testing.TB, body io.Reader) []Player {
 	t.Helper()
 	league, err := NewLeague(body)
 
@@ -141,14 +141,14 @@ func getLeagueFromResponse(t *testing.T, body io.Reader) []Player {
 	return league
 }
 
-func assertLeague(t *testing.T, got, want []Player) {
+func assertLeague(t testing.TB, got, want []Player) {
 	t.Helper()
 	if !reflect.DeepEqual(got, want) {
 		t.Errorf("got %v want %v", got, want)
 	}
 }
 
-func assertStatus(t *testing.T, got, want int) {
+func assertStatus(t testing.TB, got, want int) {
 	t.Helper()
 	if got != want {
 		t.Errorf("did not get correct status, got %d, want %d", got, want)
@@ -170,7 +170,7 @@ func newPostWinRequest(name string) *http.Request {
 	return req
 }
 
-func assertResponseBody(t *testing.T, got, want string) {
+func assertResponseBody(t testing.TB, got, want string) {
 	t.Helper()
 	if got != want {
 		t.Errorf("response body is wrong, got %q want %q", got, want)

command-line/v2/file_system_store_test.go

@@ -6,7 +6,7 @@ import (
 	"testing"
 )
 
-func createTempFile(t *testing.T, initialData string) (*os.File, func()) {
+func createTempFile(t testing.TB, initialData string) (*os.File, func()) {
 	t.Helper()
 
 	tmpfile, err := ioutil.TempFile("", "db")
@@ -109,14 +109,14 @@ func TestFileSystemStore(t *testing.T) {
 	})
 }
 
-func assertScoreEquals(t *testing.T, got, want int) {
+func assertScoreEquals(t testing.TB, got, want int) {
 	t.Helper()
 	if got != want {
 		t.Errorf("got %d want %d", got, want)
 	}
 }
 
-func assertNoError(t *testing.T, err error) {
+func assertNoError(t testing.TB, err error) {
 	t.Helper()
 	if err != nil {
 		t.Fatalf("didn't expect an error but got one, %v", err)

command-line/v2/server_test.go

@@ -123,14 +123,14 @@ func TestLeague(t *testing.T) {
 	})
 }
 
-func assertContentType(t *testing.T, response *httptest.ResponseRecorder, want string) {
+func assertContentType(t testing.TB, response *httptest.ResponseRecorder, want string) {
 	t.Helper()
 	if response.Header().Get("content-type") != want {
 		t.Errorf("response did not have content-type of %s, got %v", want, response.HeaderMap)
 	}
 }
 
-func getLeagueFromResponse(t *testing.T, body io.Reader) []Player {
+func getLeagueFromResponse(t testing.TB, body io.Reader) []Player {
 	t.Helper()
 	league, err := NewLeague(body)
 
@@ -141,14 +141,14 @@ func getLeagueFromResponse(t *testing.T, body io.Reader) []Player {
 	return league
 }
 
-func assertLeague(t *testing.T, got, want []Player) {
+func assertLeague(t testing.TB, got, want []Player) {
 	t.Helper()
 	if !reflect.DeepEqual(got, want) {
 		t.Errorf("got %v want %v", got, want)
 	}
 }
 
-func assertStatus(t *testing.T, got, want int) {
+func assertStatus(t testing.TB, got, want int) {
 	t.Helper()
 	if got != want {
 		t.Errorf("did not get correct status, got %d, want %d", got, want)
@@ -170,7 +170,7 @@ func newPostWinRequest(name string) *http.Request {
 	return req
 }
 
-func assertResponseBody(t *testing.T, got, want string) {
+func assertResponseBody(t testing.TB, got, want string) {
 	t.Helper()
 	if got != want {
 		t.Errorf("response body is wrong, got %q want %q", got, want)

command-line/v3/file_system_store_test.go

@@ -6,7 +6,7 @@ import (
 	"testing"
 )
 
-func createTempFile(t *testing.T, initialData string) (*os.File, func()) {
+func createTempFile(t testing.TB, initialData string) (*os.File, func()) {
 	t.Helper()
 
 	tmpfile, err := ioutil.TempFile("", "db")
@@ -109,14 +109,14 @@ func TestFileSystemStore(t *testing.T) {
 	})
 }
 
-func assertScoreEquals(t *testing.T, got, want int) {
+func assertScoreEquals(t testing.TB, got, want int) {
 	t.Helper()
 	if got != want {
 		t.Errorf("got %d want %d", got, want)
 	}
 }
 
-func assertNoError(t *testing.T, err error) {
+func assertNoError(t testing.TB, err error) {
 	t.Helper()
 	if err != nil {
 		t.Fatalf("didn't expect an error but got one, %v", err)

command-line/v3/server_test.go

@@ -97,14 +97,14 @@ func TestLeague(t *testing.T) {
 	})
 }
 
-func assertContentType(t *testing.T, response *httptest.ResponseRecorder, want string) {
+func assertContentType(t testing.TB, response *httptest.ResponseRecorder, want string) {
 	t.Helper()
 	if response.Header().Get("content-type") != want {
 		t.Errorf("response did not have content-type of %s, got %v", want, response.HeaderMap)
 	}
 }
 
-func getLeagueFromResponse(t *testing.T, body io.Reader) []Player {
+func getLeagueFromResponse(t testing.TB, body io.Reader) []Player {
 	t.Helper()
 	league, err := NewLeague(body)
 
@@ -115,14 +115,14 @@ func getLeagueFromResponse(t *testing.T, body io.Reader) []Player {
 	return league
 }
 
-func assertLeague(t *testing.T, got, want []Player) {
+func assertLeague(t testing.TB, got, want []Player) {
 	t.Helper()
 	if !reflect.DeepEqual(got, want) {
 		t.Errorf("got %v want %v", got, want)
 	}
 }
 
-func assertStatus(t *testing.T, got, want int) {
+func assertStatus(t testing.TB, got, want int) {
 	t.Helper()
 	if got != want {
 		t.Errorf("did not get correct status, got %d, want %d", got, want)
@@ -144,7 +144,7 @@ func newPostWinRequest(name string) *http.Request {
 	return req
 }
 
-func assertResponseBody(t *testing.T, got, want string) {
+func assertResponseBody(t testing.TB, got, want string) {
 	t.Helper()
 	if got != want {
 		t.Errorf("response body is wrong, got %q want %q", got, want)

command-line/v3/testing.go

@@ -26,7 +26,7 @@ func (s *StubPlayerStore) GetLeague() League {
 }
 
 // AssertPlayerWin allows you to spy on the store's calls to RecordWin.
-func AssertPlayerWin(t *testing.T, store *StubPlayerStore, winner string) {
+func AssertPlayerWin(t testing.TB, store *StubPlayerStore, winner string) {
 	t.Helper()
 
 	if len(store.WinCalls) != 1 {

context-aware-reader.md

@@ -75,7 +75,7 @@ func TestContextAwareReader(t *testing.T) {
 	})
 }
 
-func assertBufferHas(t *testing.T, buf []byte, want string) {
+func assertBufferHas(t testing.TB, buf []byte, want string) {
 	t.Helper()
 	got := string(buf)
 	if got != want {

hello-world.md

@@ -260,7 +260,7 @@ We can and should refactor our tests.
 ```go
 func TestHello(t *testing.T) {
 
-	assertCorrectMessage := func(t *testing.T, got, want string) {
+	assertCorrectMessage := func(t testing.TB, got, want string) {
 		t.Helper()
 		if got != want {
 			t.Errorf("got %q want %q", got, want)
@@ -286,6 +286,8 @@ What have we done here?
 
 We've refactored our assertion into a function. This reduces duplication and improves readability of our tests. In Go you can declare functions inside other functions and assign them to variables. You can then call them, just like normal functions. We need to pass in `t *testing.T` so that we can tell the test code to fail when we need to.
 
+For helper functions, it's a good idea to accept a `testing.TB` which is an interface that `*testing.T` and `*testing.B` both satisfy, so you can call helper functions from a test, or a benchmark.
+
 `t.Helper()` is needed to tell the test suite that this method is a helper. By doing this when it fails the line number reported will be in our _function call_ rather than inside our test helper. This will help other developers track down problems easier. If you still don't understand, comment it out, make a test fail and observe the test output.
 
 Now that we have a well-written failing test, let's fix the code, using an `if`.

hello-world/v5/hello_test.go

@@ -4,7 +4,7 @@ import "testing"
 
 func TestHello(t *testing.T) {
 
-	assertCorrectMessage := func(t *testing.T, got, want string) {
+	assertCorrectMessage := func(t testing.TB, got, want string) {
 		t.Helper()
 		if got != want {
 			t.Errorf("got %q want %q", got, want)

hello-world/v6/hello_test.go

@@ -4,7 +4,7 @@ import "testing"
 
 func TestHello(t *testing.T) {
 
-	assertCorrectMessage := func(t *testing.T, got, want string) {
+	assertCorrectMessage := func(t testing.TB, got, want string) {
 		t.Helper()
 		if got != want {
 			t.Errorf("got %q want %q", got, want)

hello-world/v8/hello_test.go

@@ -4,7 +4,7 @@ import "testing"
 
 func TestHello(t *testing.T) {
 
-	assertCorrectMessage := func(t *testing.T, got, want string) {
+	assertCorrectMessage := func(t testing.TB, got, want string) {
 		t.Helper()
 		if got != want {
 			t.Errorf("got %q want %q", got, want)

http-server.md

@@ -306,7 +306,7 @@ func newGetScoreRequest(name string) *http.Request {
 	return req
 }
 
-func assertResponseBody(t *testing.T, got, want string) {
+func assertResponseBody(t testing.TB, got, want string) {
 	t.Helper()
 	if got != want {
 		t.Errorf("response body is wrong, got %q want %q", got, want)
@@ -601,7 +601,7 @@ func TestGETPlayers(t *testing.T) {
 	})
 }
 
-func assertStatus(t *testing.T, got, want int) {
+func assertStatus(t testing.TB, got, want int) {
 	t.Helper()
 	if got != want {
 		t.Errorf("did not get correct status, got %d, want %d", got, want)
@@ -613,7 +613,7 @@ func newGetScoreRequest(name string) *http.Request {
 	return req
 }
 
-func assertResponseBody(t *testing.T, got, want string) {
+func assertResponseBody(t testing.TB, got, want string) {
 	t.Helper()
 	if got != want {
 		t.Errorf("response body is wrong, got %q want %q", got, want)

http-server/v2/server_test.go

@@ -63,7 +63,7 @@ func TestGETPlayers(t *testing.T) {
 	}
 }
 
-func assertStatus(t *testing.T, got, want int) {
+func assertStatus(t testing.TB, got, want int) {
 	t.Helper()
 	if got != want {
 		t.Errorf("did not get correct status, got %d, want %d", got, want)
@@ -75,7 +75,7 @@ func newGetScoreRequest(name string) *http.Request {
 	return req
 }
 
-func assertResponseBody(t *testing.T, got, want string) {
+func assertResponseBody(t testing.TB, got, want string) {
 	t.Helper()
 	if got != want {
 		t.Errorf("response body is wrong, got %q want %q", got, want)

http-server/v3/server_test.go

@@ -79,7 +79,7 @@ func TestStoreWins(t *testing.T) {
 	})
 }
 
-func assertStatus(t *testing.T, got, want int) {
+func assertStatus(t testing.TB, got, want int) {
 	t.Helper()
 	if got != want {
 		t.Errorf("did not get correct status, got %d, want %d", got, want)
@@ -91,7 +91,7 @@ func newGetScoreRequest(name string) *http.Request {
 	return req
 }
 
-func assertResponseBody(t *testing.T, got, want string) {
+func assertResponseBody(t testing.TB, got, want string) {
 	t.Helper()
 	if got != want {
 		t.Errorf("response body is wrong, got %q want %q", got, want)

http-server/v4/server_test.go

@@ -96,7 +96,7 @@ func TestStoreWins(t *testing.T) {
 	})
 }
 
-func assertStatus(t *testing.T, got, want int) {
+func assertStatus(t testing.TB, got, want int) {
 	t.Helper()
 	if got != want {
 		t.Errorf("did not get correct status, got %d, want %d", got, want)
@@ -108,7 +108,7 @@ func newGetScoreRequest(name string) *http.Request {
 	return req
 }
 
-func assertResponseBody(t *testing.T, got, want string) {
+func assertResponseBody(t testing.TB, got, want string) {
 	t.Helper()
 	if got != want {
 		t.Errorf("response body is wrong, got %q want %q", got, want)

http-server/v5/server_test.go

@@ -96,7 +96,7 @@ func TestStoreWins(t *testing.T) {
 	})
 }
 
-func assertStatus(t *testing.T, got, want int) {
+func assertStatus(t testing.TB, got, want int) {
 	t.Helper()
 	if got != want {
 		t.Errorf("did not get correct status, got %d, want %d", got, want)
@@ -113,7 +113,7 @@ func newPostWinRequest(name string) *http.Request {
 	return req
 }
 
-func assertResponseBody(t *testing.T, got, want string) {
+func assertResponseBody(t testing.TB, got, want string) {
 	t.Helper()
 	if got != want {
 		t.Errorf("response body is wrong, got %q want %q", got, want)