group: fix testing to be deterministic

group_test.go

@@ -2,6 +2,7 @@ package multierror
 
 import (
 	"errors"
+	"strings"
 	"testing"
 )
 
@@ -10,14 +11,14 @@ func TestGroup(t *testing.T) {
 	err2 := errors.New("group_test: 2")
 
 	cases := []struct {
-		errs   []error
-		result error
+		errs      []error
+		nilResult bool
 	}{
-		{errs: []error{}},
-		{errs: []error{nil}},
-		{errs: []error{err1}, result: Append(nil, err1)},
-		{errs: []error{err1, nil}, result: Append(nil, err1)},
-		{errs: []error{err1, nil, err2}, result: Append(err2, err1)},
+		{errs: []error{}, nilResult: true},
+		{errs: []error{nil}, nilResult: true},
+		{errs: []error{err1}},
+		{errs: []error{err1, nil}},
+		{errs: []error{err1, nil, err2}},
 	}
 
 	for _, tc := range cases {
@@ -30,14 +31,14 @@ func TestGroup(t *testing.T) {
 		}
 
 		gErr := g.Wait()
-		if gErr == nil && tc.result != nil {
-			t.Fatalf("Group.Wait() was nil but expected: %v", tc.result)
-			return
-		} else if tc.result == nil && gErr != nil {
-			t.Fatalf("Group.Wait() was expected to be nil, actual: %v", gErr)
-			return
-		} else if gErr != nil && tc.result != nil && gErr.Error() != tc.result.Error() {
-			t.Errorf("Group.Wait() returned the wrong error, expected: %v, actual: %v", tc.result, gErr)
+		if gErr != nil {
+			for i := range tc.errs {
+				if tc.errs[i] != nil && !strings.Contains(gErr.Error(), tc.errs[i].Error()) {
+					t.Fatalf("expected error to contain %q, actual: %v", tc.errs[i].Error(), gErr)
+				}
+			}
+		} else if !tc.nilResult {
+			t.Fatalf("Group.Wait() should not have returned nil for errs: %v", tc.errs)
 		}
 	}
 }