Add Cleanup, clarify versioning in README

README.md

@@ -38,6 +38,14 @@ You can also call the test helper at runtime if needed:
         TestHelper(&testing.RuntimeT{})
     }
 
+## Versioning
+
+The tagged version matches the version of Go that the interface is
+compatible with. For example, the version "1.14.0" is for Go 1.14 and
+introduced the `Cleanup` function. The patch version (the ".0" in the
+prior example) is used to fix any bugs found in this library and has no
+correlation to the supported Go version.
+
 ## Why?!
 
 **Why would I call a test helper that takes a *testing.T at runtime?**

go.mod

@@ -1 +1,3 @@
 module github.com/mitchellh/go-testing-interface
+
+go 1.14

testing.go

@@ -1,5 +1,3 @@
-// +build !go1.9
-
 package testing
 
 import (
@@ -12,13 +10,15 @@ import (
 // In unit tests you can just pass a *testing.T struct. At runtime, outside
 // of tests, you can pass in a RuntimeT struct from this package.
 type T interface {
+	Cleanup(func())
 	Error(args ...interface{})
 	Errorf(format string, args ...interface{})
 	Fail()
 	FailNow()
 	Failed() bool
 	Fatal(args ...interface{})
 	Fatalf(format string, args ...interface{})
+	Helper()
 	Log(args ...interface{})
 	Logf(format string, args ...interface{})
 	Name() string
@@ -31,10 +31,13 @@ type T interface {
 // RuntimeT implements T and can be instantiated and run at runtime to
 // mimic *testing.T behavior. Unlike *testing.T, this will simply panic
 // for calls to Fatal. For calls to Error, you'll have to check the errors
-// list to determine whether to exit yourself. Name and Skip methods are
-// unimplemented noops.
+// list to determine whether to exit yourself.
+//
+// Cleanup does NOT work, so if you're using a helper that uses Cleanup,
+// there may be dangling resources.
 type RuntimeT struct {
-	failed bool
+	skipped bool
+	failed  bool
 }
 
 func (t *RuntimeT) Error(args ...interface{}) {
@@ -43,20 +46,10 @@ func (t *RuntimeT) Error(args ...interface{}) {
 }
 
 func (t *RuntimeT) Errorf(format string, args ...interface{}) {
-	log.Println(fmt.Sprintf(format, args...))
+	log.Printf(format, args...)
 	t.Fail()
 }
 
-func (t *RuntimeT) Fatal(args ...interface{}) {
-	log.Println(fmt.Sprintln(args...))
-	t.FailNow()
-}
-
-func (t *RuntimeT) Fatalf(format string, args ...interface{}) {
-	log.Println(fmt.Sprintf(format, args...))
-	t.FailNow()
-}
-
 func (t *RuntimeT) Fail() {
 	t.failed = true
 }
@@ -69,6 +62,16 @@ func (t *RuntimeT) Failed() bool {
 	return t.failed
 }
 
+func (t *RuntimeT) Fatal(args ...interface{}) {
+	log.Print(args...)
+	t.FailNow()
+}
+
+func (t *RuntimeT) Fatalf(format string, args ...interface{}) {
+	log.Printf(format, args...)
+	t.FailNow()
+}
+
 func (t *RuntimeT) Log(args ...interface{}) {
 	log.Println(fmt.Sprintln(args...))
 }
@@ -77,8 +80,28 @@ func (t *RuntimeT) Logf(format string, args ...interface{}) {
 	log.Println(fmt.Sprintf(format, args...))
 }
 
-func (t *RuntimeT) Name() string                             { return "" }
-func (t *RuntimeT) Skip(args ...interface{})                 {}
-func (t *RuntimeT) SkipNow()                                 {}
-func (t *RuntimeT) Skipf(format string, args ...interface{}) {}
-func (t *RuntimeT) Skipped() bool                            { return false }
+func (t *RuntimeT) Name() string {
+	return ""
+}
+
+func (t *RuntimeT) Skip(args ...interface{}) {
+	log.Print(args...)
+	t.SkipNow()
+}
+
+func (t *RuntimeT) SkipNow() {
+	t.skipped = true
+}
+
+func (t *RuntimeT) Skipf(format string, args ...interface{}) {
+	log.Printf(format, args...)
+	t.SkipNow()
+}
+
+func (t *RuntimeT) Skipped() bool {
+	return t.skipped
+}
+
+func (t *RuntimeT) Helper() {}
+
+func (t *RuntimeT) Cleanup(func()) {}