test: test joined error for go1.20 and later versions.

Signed-off-by: ghosind <ghosind@gmail.com>

Author: ghosind

errors_go120_test.go

@@ -0,0 +1,21 @@
+//go:build go1.20
+
+package assert
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestIsErrorWithJoinedErrors(t *testing.T) {
+	a := New(t)
+	mockA := New(new(testing.T))
+
+	err1 := errors.New("error 1")
+	err2 := errors.New("error 2")
+	err3 := errors.New("error 3")
+
+	testIsError(a, mockA, errors.Join(err1, err2), err1, true)
+	testIsError(a, mockA, errors.Join(err1, err2), err2, true)
+	testIsError(a, mockA, errors.Join(err1, err2), err3, false)
+}

errors_test.go

@@ -17,9 +17,6 @@ func TestIsError(t *testing.T) {
 	testIsError(a, mockA, err1, err1, true)
 	testIsError(a, mockA, err1, err2, false)
 	testIsError(a, mockA, err1, err3, false)
-	testIsError(a, mockA, errors.Join(err1, err2), err1, true)
-	testIsError(a, mockA, errors.Join(err1, err2), err2, true)
-	testIsError(a, mockA, errors.Join(err1, err2), err3, false)
 }
 
 func testIsError(a, mockA *Assertion, err, target error, isError bool) {