Add test case for internal/errors/io.go (#910)

* feat: Add test case and godoc comment

Signed-off-by: hlts2 <hiroto.funakoshi.hiroto@gmail.com>

* 🤖 Update license headers / Format go codes and yaml files

Signed-off-by: vdaas-ci <ci@vdaas.org>

Co-authored-by: vdaas-ci <ci@vdaas.org>

internal/errors/io.go

@@ -18,15 +18,17 @@
 package errors
 
 var (
-	// io
+	// NewErrContextNotProvided represents a function to generate an error that the context is not provided.
 	NewErrContextNotProvided = func() error {
 		return New("context not provided")
 	}
 
+	// NewErrReaderNotProvided represents a function to generate an error that the io.Reader is not provided.
 	NewErrReaderNotProvided = func() error {
 		return New("io.Reader not provided")
 	}
 
+	// NewErrWriterNotProvided represents a function to generate an error that the io.Writer is not provided.
 	NewErrWriterNotProvided = func() error {
 		return New("io.Writer not provided")
 	}

internal/errors/io_test.go

@@ -0,0 +1,156 @@
+//
+// Copyright (C) 2019-2021 vdaas.org vald team <vald@vdaas.org>
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+package errors
+
+import "testing"
+
+func TestNewErrContextNotProvided(t *testing.T) {
+	type want struct {
+		want error
+	}
+	type test struct {
+		name       string
+		want       want
+		checkFunc  func(want, error) error
+		beforeFunc func()
+		afterFunc  func()
+	}
+	defaultCheckFunc := func(w want, got error) error {
+		if !Is(got, w.want) {
+			return Errorf("got: \"%#v\",\n\t\t\t\twant: \"%#v\"", got, w.want)
+		}
+		return nil
+	}
+	tests := []test{
+		{
+			name: "return ErrContextNotProvided error",
+			want: want{
+				want: New("context not provided"),
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(tt *testing.T) {
+			if test.beforeFunc != nil {
+				test.beforeFunc()
+			}
+			if test.afterFunc != nil {
+				defer test.afterFunc()
+			}
+			if test.checkFunc == nil {
+				test.checkFunc = defaultCheckFunc
+			}
+
+			got := NewErrContextNotProvided()
+			if err := test.checkFunc(test.want, got); err != nil {
+				tt.Errorf("error = %v", err)
+			}
+		})
+	}
+}
+
+func TestNewErrReaderNotProvided(t *testing.T) {
+	type want struct {
+		want error
+	}
+	type test struct {
+		name       string
+		want       want
+		checkFunc  func(want, error) error
+		beforeFunc func()
+		afterFunc  func()
+	}
+	defaultCheckFunc := func(w want, got error) error {
+		if !Is(got, w.want) {
+			return Errorf("got: \"%#v\",\n\t\t\t\twant: \"%#v\"", got, w.want)
+		}
+		return nil
+	}
+	tests := []test{
+		{
+			name: "return ErrReaderNotProvided error",
+			want: want{
+				want: New("io.Reader not provided"),
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(tt *testing.T) {
+			if test.beforeFunc != nil {
+				test.beforeFunc()
+			}
+			if test.afterFunc != nil {
+				defer test.afterFunc()
+			}
+			if test.checkFunc == nil {
+				test.checkFunc = defaultCheckFunc
+			}
+
+			got := NewErrReaderNotProvided()
+			if err := test.checkFunc(test.want, got); err != nil {
+				tt.Errorf("error = %v", err)
+			}
+		})
+	}
+}
+
+func TestNewErrWriterNotProvided(t *testing.T) {
+	type want struct {
+		want error
+	}
+	type test struct {
+		name       string
+		want       want
+		checkFunc  func(want, error) error
+		beforeFunc func()
+		afterFunc  func()
+	}
+	defaultCheckFunc := func(w want, got error) error {
+		if !Is(got, w.want) {
+			return Errorf("got: \"%#v\",\n\t\t\t\twant: \"%#v\"", got, w.want)
+		}
+		return nil
+	}
+	tests := []test{
+		{
+			name: "return ErrWriterNotProvided error",
+			want: want{
+				want: New("io.Writer not provided"),
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(tt *testing.T) {
+			if test.beforeFunc != nil {
+				test.beforeFunc()
+			}
+			if test.afterFunc != nil {
+				defer test.afterFunc()
+			}
+			if test.checkFunc == nil {
+				test.checkFunc = defaultCheckFunc
+			}
+
+			got := NewErrWriterNotProvided()
+			if err := test.checkFunc(test.want, got); err != nil {
+				tt.Errorf("error = %v", err)
+			}
+		})
+	}
+}