assert: ErrorIs

.golangci.yml

@@ -15,7 +15,7 @@ issues:
     - text: 'always receives'
       linters: [unparam]
     - path: _test\.go
-      linters: [errcheck, staticcheck]
+      linters: [errcheck, staticcheck, lll]
     - path: internal/difflib/difflib\.go
       text: .
     - text: 'return value of .*Close` is not checked'

assert/assert_go113.go

@@ -0,0 +1,20 @@
+// +build go1.13
+
+package assert
+
+import (
+	"gotest.tools/v3/assert/cmp"
+	"gotest.tools/v3/internal/assert"
+)
+
+// ErrorIs fails the test if err is nil, or the error does not match expected
+// when compared using errors.Is. See https://golang.org/pkg/errors/#Is for
+// accepted argument values.
+func ErrorIs(t TestingT, err error, expected error, msgAndArgs ...interface{}) {
+	if ht, ok := t.(helperT); ok {
+		ht.Helper()
+	}
+	if !assert.Eval(t, assert.ArgsAfterT, cmp.ErrorIs(err, expected), msgAndArgs...) {
+		t.FailNow()
+	}
+}

assert/assert_go113_test.go

@@ -0,0 +1,35 @@
+// +build go1.13
+
+package assert
+
+import (
+	"fmt"
+	"os"
+	"testing"
+)
+
+func TestErrorIs(t *testing.T) {
+	t.Run("nil error", func(t *testing.T) {
+		fakeT := &fakeTestingT{}
+
+		var err error
+		ErrorIs(fakeT, err, os.ErrNotExist)
+		expected := `assertion failed: error is nil, not "file does not exist" (os.ErrNotExist *errors.errorString)`
+		expectFailNowed(t, fakeT, expected)
+	})
+	t.Run("different error", func(t *testing.T) {
+		fakeT := &fakeTestingT{}
+
+		err := fmt.Errorf("the actual error")
+		ErrorIs(fakeT, err, os.ErrNotExist)
+		expected := `assertion failed: error is "the actual error" (err *errors.errorString), not "file does not exist" (os.ErrNotExist *errors.errorString)`
+		expectFailNowed(t, fakeT, expected)
+	})
+	t.Run("same error", func(t *testing.T) {
+		fakeT := &fakeTestingT{}
+
+		err := fmt.Errorf("some wrapping: %w", os.ErrNotExist)
+		ErrorIs(fakeT, err, os.ErrNotExist)
+		expectSuccess(t, fakeT)
+	})
+}

assert/cmp/compare_go113.go

@@ -0,0 +1,30 @@
+// +build go1.13
+
+package cmp
+
+import (
+	"errors"
+)
+
+// ErrorIs succeeds if errors.Is(actual, expected) returns true. See
+// https://golang.org/pkg/errors/#Is for accepted argument values.
+func ErrorIs(actual error, expected error) Comparison {
+	return func() Result {
+		if errors.Is(actual, expected) {
+			return ResultSuccess
+		}
+
+		return ResultFailureTemplate(`error is
+			{{- if not .Data.a }} nil,{{ else }}
+			{{- printf " \"%v\"" .Data.a}} (
+				{{- with callArg 0 }}{{ formatNode . }} {{end -}}
+				{{- printf "%T" .Data.a -}}
+			),
+			{{- end }} not {{ printf "\"%v\"" .Data.x}} (
+				{{- with callArg 1 }}{{ formatNode . }} {{end -}}
+				{{- printf "%T" .Data.x -}}
+			)`,
+			map[string]interface{}{"a": actual, "x": expected})
+		//return ResultFailure(fmt.Sprintf("error is %v, not %v (%T)", actual, target, target))
+	}
+}

assert/cmp/compare_go113_test.go

@@ -0,0 +1,42 @@
+// +build go1.13
+
+package cmp
+
+import (
+	"go/ast"
+	"os"
+	"testing"
+)
+
+func TestErrorIs(t *testing.T) {
+	t.Run("equal", func(t *testing.T) {
+		result := ErrorIs(stubError{}, stubError{})()
+		assertSuccess(t, result)
+	})
+	t.Run("actual is nil", func(t *testing.T) {
+		result := ErrorIs(nil, stubError{})()
+		args := []ast.Expr{
+			&ast.Ident{Name: "err"},
+			&ast.StarExpr{
+				X: &ast.SelectorExpr{
+					X:   &ast.Ident{Name: "errors"},
+					Sel: &ast.Ident{Name: "errorString"},
+				}},
+		}
+		expected := `error is nil, not "stub error" (*errors.errorString cmp.stubError)`
+		assertFailureTemplate(t, result, args, expected)
+	})
+	t.Run("not equal", func(t *testing.T) {
+		result := ErrorIs(os.ErrClosed, stubError{})()
+		args := []ast.Expr{
+			&ast.Ident{Name: "err"},
+			&ast.StarExpr{
+				X: &ast.SelectorExpr{
+					X:   &ast.Ident{Name: "errors"},
+					Sel: &ast.Ident{Name: "errorString"},
+				}},
+		}
+		expected := `error is "file already closed" (err *errors.errorString), not "stub error" (*errors.errorString cmp.stubError)`
+		assertFailureTemplate(t, result, args, expected)
+	})
+}

poll/check.go

@@ -11,16 +11,20 @@ type Check func(t LogT) Result
 // FileExists looks on filesystem and check that path exists.
 func FileExists(path string) Check {
 	return func(t LogT) Result {
+		if h, ok := t.(helperT); ok {
+			h.Helper()
+		}
+
 		_, err := os.Stat(path)
-		if os.IsNotExist(err) {
+		switch {
+		case os.IsNotExist(err):
 			t.Logf("waiting on file %s to exist", path)
 			return Continue("file %s does not exist", path)
-		}
-		if err != nil {
+		case err != nil:
 			return Error(err)
+		default:
+			return Success()
 		}
-
-		return Success()
 	}
 }
 
@@ -29,6 +33,10 @@ func FileExists(path string) Check {
 // address parameters.
 func Connection(network, address string) Check {
 	return func(t LogT) Result {
+		if h, ok := t.(helperT); ok {
+			h.Helper()
+		}
+
 		_, err := net.Dial(network, address)
 		if err != nil {
 			t.Logf("waiting on socket %s://%s to be available...", network, address)