Add comparison expression mutator

Author: jackwilsdon

cmd/go-mutesting/main_test.go

@@ -15,7 +15,7 @@ func TestMain(t *testing.T) {
 		"../../example",
 		[]string{"--debug", "--exec-timeout", "1"},
 		returnOk,
-		"The mutation score is 0.500000 (8 passed, 8 failed, 8 duplicated, 0 skipped, total is 16)",
+		"The mutation score is 0.450000 (9 passed, 11 failed, 8 duplicated, 0 skipped, total is 20)",
 	)
 }
 
@@ -25,7 +25,7 @@ func TestMainRecursive(t *testing.T) {
 		"../../example",
 		[]string{"--debug", "--exec-timeout", "1", "./..."},
 		returnOk,
-		"The mutation score is 0.529412 (9 passed, 8 failed, 8 duplicated, 0 skipped, total is 17)",
+		"The mutation score is 0.476190 (10 passed, 11 failed, 8 duplicated, 0 skipped, total is 21)",
 	)
 }
 
@@ -35,7 +35,7 @@ func TestMainFromOtherDirectory(t *testing.T) {
 		"../..",
 		[]string{"--debug", "--exec-timeout", "1", "github.com/zimmski/go-mutesting/example"},
 		returnOk,
-		"The mutation score is 0.500000 (8 passed, 8 failed, 8 duplicated, 0 skipped, total is 16)",
+		"The mutation score is 0.450000 (9 passed, 11 failed, 8 duplicated, 0 skipped, total is 20)",
 	)
 }
 

mutator/expression/comparison.go

@@ -0,0 +1,45 @@
+package expression
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"github.com/zimmski/go-mutesting/mutator"
+)
+
+func init() {
+	mutator.Register("expression/comparison", MutatorComparison)
+}
+
+var comparisonMutations = map[token.Token]token.Token{
+	token.LSS: token.LEQ,
+	token.LEQ: token.LSS,
+	token.GTR: token.GEQ,
+	token.GEQ: token.GTR,
+}
+
+// MutatorComparison implements a mutator to change comparisons.
+func MutatorComparison(pkg *types.Package, info *types.Info, node ast.Node) []mutator.Mutation {
+	n, ok := node.(*ast.BinaryExpr)
+	if !ok {
+		return nil
+	}
+
+	o := n.Op
+	r, ok := comparisonMutations[n.Op]
+	if !ok {
+		return nil
+	}
+
+	return []mutator.Mutation{
+		mutator.Mutation{
+			Change: func() {
+				n.Op = r
+			},
+			Reset: func() {
+				n.Op = o
+			},
+		},
+	}
+}

mutator/expression/comparison_test.go

@@ -0,0 +1,16 @@
+package expression
+
+import (
+	"testing"
+
+	"github.com/zimmski/go-mutesting/test"
+)
+
+func TestMutatorComparison(t *testing.T) {
+	test.Mutator(
+		t,
+		MutatorComparison,
+		"../../testdata/expression/comparison.go",
+		4,
+	)
+}

testdata/expression/comparison.go

@@ -0,0 +1,27 @@
+// +build example-main
+
+package main
+
+import "fmt"
+
+func main() {
+	if 1 > 2 {
+		fmt.Printf("1 is greater than 2!")
+	}
+
+	if 1 < 2 {
+		fmt.Printf("1 is less than 2!")
+	}
+
+	if 1 <= 2 {
+		fmt.Printf("1 is less than or equal to 2!")
+	}
+
+	if 1 >= 2 {
+		fmt.Printf("1 is greater than or equal to 2!")
+	}
+
+	if 1 == 2 {
+		fmt.Print("1 is equal to 2!")
+	}
+}

testdata/expression/comparison.go.0.go

@@ -0,0 +1,27 @@
+// +build example-main
+
+package main
+
+import "fmt"
+
+func main() {
+	if 1 >= 2 {
+		fmt.Printf("1 is greater than 2!")
+	}
+
+	if 1 < 2 {
+		fmt.Printf("1 is less than 2!")
+	}
+
+	if 1 <= 2 {
+		fmt.Printf("1 is less than or equal to 2!")
+	}
+
+	if 1 >= 2 {
+		fmt.Printf("1 is greater than or equal to 2!")
+	}
+
+	if 1 == 2 {
+		fmt.Print("1 is equal to 2!")
+	}
+}

testdata/expression/comparison.go.1.go

@@ -0,0 +1,27 @@
+// +build example-main
+
+package main
+
+import "fmt"
+
+func main() {
+	if 1 > 2 {
+		fmt.Printf("1 is greater than 2!")
+	}
+
+	if 1 <= 2 {
+		fmt.Printf("1 is less than 2!")
+	}
+
+	if 1 <= 2 {
+		fmt.Printf("1 is less than or equal to 2!")
+	}
+
+	if 1 >= 2 {
+		fmt.Printf("1 is greater than or equal to 2!")
+	}
+
+	if 1 == 2 {
+		fmt.Print("1 is equal to 2!")
+	}
+}

testdata/expression/comparison.go.2.go

@@ -0,0 +1,27 @@
+// +build example-main
+
+package main
+
+import "fmt"
+
+func main() {
+	if 1 > 2 {
+		fmt.Printf("1 is greater than 2!")
+	}
+
+	if 1 < 2 {
+		fmt.Printf("1 is less than 2!")
+	}
+
+	if 1 < 2 {
+		fmt.Printf("1 is less than or equal to 2!")
+	}
+
+	if 1 >= 2 {
+		fmt.Printf("1 is greater than or equal to 2!")
+	}
+
+	if 1 == 2 {
+		fmt.Print("1 is equal to 2!")
+	}
+}

testdata/expression/comparison.go.3.go

@@ -0,0 +1,27 @@
+// +build example-main
+
+package main
+
+import "fmt"
+
+func main() {
+	if 1 > 2 {
+		fmt.Printf("1 is greater than 2!")
+	}
+
+	if 1 < 2 {
+		fmt.Printf("1 is less than 2!")
+	}
+
+	if 1 <= 2 {
+		fmt.Printf("1 is less than or equal to 2!")
+	}
+
+	if 1 > 2 {
+		fmt.Printf("1 is greater than or equal to 2!")
+	}
+
+	if 1 == 2 {
+		fmt.Print("1 is equal to 2!")
+	}
+}