错误的断言包含并等于未按预期工作

Question

我正在断言函数中的错误，我已经为函数提供了这样的输入，以便它将引发错误。我想检查错误是否正确。这是我的函数：func validateK8ResourcesLength(resource prm.Resource) error {    name := resource.GetName()    namespace := resource.GetNamespace()    k8sResourceName := fmt.Sprintf("%s-%s", namespace, name)    if len(k8sResourceName) > common.K8sNameLength {        return fmt.Errorf("Namespace (%s) and Name (%s) length combined must not be greater than 48 chars", namespace, name)    }    return nil}我的测试代码：func TestK8testing(t *testing.T) {    ctrl := gomock.NewController(t)    defer ctrl.Finish()    mockContext := prmmock.NewMockStepContext(ctrl)    mockResource := prmmock.NewMockResource(ctrl)    mockClient := prmmock.NewMockClient(ctrl)    // testClient := fake.NewFakeClientWithScheme(runtime.NewScheme())    lables := make(map[string]string)    mockClient.EXPECT().GetResource(gomock.Any(), gomock.Any()).Return(mockResource, nil).AnyTimes()    mockContext.EXPECT().Resource().Return(mockResource).AnyTimes()    mockResource.EXPECT().GetKind().Return("data-movement-v1-nonexist").AnyTimes()    mockResource.EXPECT().GetName().Return("test-dm-more-then-forty-eight-charactors-this-should-fail").AnyTimes()    mockResource.EXPECT().GetNamespace().Return("ns-more-then-forty-eight-charactors-this-should-fail").AnyTimes()    mockResource.EXPECT().GetLabels().Return(lables).AnyTimes()    mockResource.EXPECT().GetID().Return(prm.NewResourceID("hcc-dm", "data-movement-v1", "test-dm")).AnyTimes()    err := validateK8ResourcesLength(mockResource)    assert.Error(t, err)    if assert.Error(t, err) {        //assert.Contains(t, err, "length combined must not be greater")        assert.Equal(t, "Namespace (ns-more-then-forty-eight-charactors-this-should-fail) and Name (test-dm-more-then-forty-eight-charactors-this-should-fail) length combined must not be greater than 48 chars", err)    }}我的代码有什么问题？我也不起作用。assert.contains

Answer 1

错误内置类型是一个接口：

type error interface {
    Error() string
    }

因此，如果要检查错误值，则实际上需要调用该方法。Error() string

此资源介绍了基础知识：https://blog.golang.org/error-handling-and-go

以及 Go 1.13 对基础知识的扩展：https://blog.golang.org/go1.13-errors