support OpenSuite interface with Spec to enable non-testcase specific…

… suite generation

Spec.go

@@ -15,7 +15,7 @@ import (
 
 // NewSpec create new Spec struct that is ready for usage.
 func NewSpec(tb testing.TB, opts ...SpecOption) *Spec {
-	tb = ensureTB(tb)
+	tb, opts = checkSuite(tb, opts)
 	tb.Helper()
 	var s *Spec
 	switch tb := tb.(type) {
@@ -636,9 +636,17 @@ func (spec *Spec) getIsSuite() bool {
 	return false
 }
 
-func ensureTB(tb testing.TB) testing.TB {
+func checkSuite(tb testing.TB, opts []SpecOption) (testing.TB, []SpecOption) {
 	if tb == nil {
-		return internal.SuiteNullTB{}
+		return internal.SuiteNullTB{}, append(opts, AsSuite())
 	}
-	return tb
+	return tb, opts
 }
+
+func (spec *Spec) AsSuite() SpecSuite { return SpecSuite{S: spec} }
+
+type SpecSuite struct{ S *Spec }
+
+func (suite SpecSuite) Test(t *testing.T)      { suite.S.Spec(NewSpec(t)) }
+func (suite SpecSuite) Benchmark(b *testing.B) { suite.S.Spec(NewSpec(b)) }
+func (suite SpecSuite) Spec(s *Spec)           { suite.S.Spec(s) }

Spec_test.go

@@ -1391,7 +1391,7 @@ func TestSpec_spike(t *testing.T) {
 
 }
 
-func TestAsSuite(t *testing.T) {
+func TestSpec_Spec(t *testing.T) {
 	t.Run("runs only when Spec method is called", func(t *testing.T) {
 		s := testcase.NewSpec(nil, testcase.AsSuite())
 		s.Sequential()
@@ -1466,7 +1466,22 @@ func TestAsSuite(t *testing.T) {
 
 		assert.True(t, ran)
 	})
+	t.Run("Spec made with nil testing.TB is interpreted as a Suite", func(t *testing.T) {
+		var ran bool
+		s1 := testcase.NewSpec(nil)
+		s1.Test("", func(t *testcase.T) { ran = true })
+
+		s2 := testcase.NewSpec(nil)
+		s1.Spec(s2) // s1 merge into s2
+
+		assert.False(t, ran)
+
+		dtb := &doubles.TB{}
+		s3 := testcase.NewSpec(dtb)
+		s2.Spec(s3) // execute
 
+		assert.True(t, ran)
+	})
 	t.Run("when Spec.Spec is called on non Suite Spec", func(t *testing.T) {
 		dtb := &doubles.TB{}
 		s := testcase.NewSpec(dtb)
@@ -1475,3 +1490,40 @@ func TestAsSuite(t *testing.T) {
 		})
 	})
 }
+
+func TestSpec_AsSuite(t *testing.T) {
+	t.Run(".Suite", func(t *testing.T) {
+		var ran bool
+		s1 := testcase.NewSpec(nil)
+		s1.Test("", func(t *testcase.T) { ran = true })
+		assert.False(t, ran)
+
+		dtb := &doubles.TB{}
+		s2 := testcase.NewSpec(dtb)
+		s1.AsSuite().Spec(s2) // execute
+		assert.True(t, ran)
+	})
+	t.Run(".Test", func(t *testing.T) {
+		var ran bool
+		s1 := testcase.NewSpec(nil)
+		s1.Test("", func(t *testcase.T) { ran = true })
+		assert.False(t, ran)
+
+		s1.AsSuite().Test(t) // execute
+		assert.True(t, ran)
+	})
+	t.Run(".Benchmark", func(t *testing.T) {
+		var ran bool
+		s1 := testcase.NewSpec(nil)
+		s1.Test("", func(t *testcase.T) {
+			ran = true
+			t.Skip()
+		})
+		assert.False(t, ran)
+
+		testing.Benchmark(func(b *testing.B) {
+			s1.AsSuite().Benchmark(b) // execute
+		})
+		assert.True(t, ran)
+	})
+}

examples_test.go

@@ -1512,6 +1512,12 @@ func Example_global_Before() {
 	})
 }
 
+func ExampleAsSuite() {
+	var tb testing.TB
+	s := testcase.NewSpec(tb)
+	s.Context("my example testing suite", exampleSuite().Spec)
+}
+
 func exampleSuite() testcase.Suite {
 	s := testcase.NewSpec(nil, testcase.AsSuite())
 	s.Test("foo", func(t *testcase.T) {
@@ -1520,8 +1526,20 @@ func exampleSuite() testcase.Suite {
 	return s
 }
 
-func ExampleAsSuite() {
-	var tb testing.TB
-	s := testcase.NewSpec(tb)
-	s.Context("my example testing suite", exampleSuite().Spec)
+func ExampleSpec_AsSuite() {
+	suite := exampleOpenSuite()
+
+	var t *testing.T
+	suite.Test(t)
+
+	var b *testing.B
+	suite.Benchmark(b)
+}
+
+func exampleOpenSuite() testcase.OpenSuite {
+	s := testcase.NewSpec(nil, testcase.AsSuite())
+	s.Test("foo", func(t *testcase.T) {
+		// OK
+	})
+	return s.AsSuite()
 }