Add unit test for errors middleware

Signed-off-by: Tw <tw19881113@gmail.com>

middleware/errors/errors_test.go

+package errors
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"log"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/mholt/caddy/middleware"
+)
+
+func TestErrors(t *testing.T) {
+	// create a temporary page
+	path := filepath.Join(os.TempDir(), "errors_test.html")
+	f, err := os.Create(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(path)
+
+	const content = "This is a error page"
+	_, err = f.WriteString(content)
+	if err != nil {
+		t.Fatal(err)
+	}
+	f.Close()
+
+	buf := bytes.Buffer{}
+	em := ErrorHandler{
+		ErrorPages: make(map[int]string),
+		Log:        log.New(&buf, "", 0),
+	}
+	em.ErrorPages[http.StatusNotFound] = path
+	em.ErrorPages[http.StatusForbidden] = "not_exist_file"
+	_, notExistErr := os.Open("not_exist_file")
+
+	testErr := errors.New("test error")
+	tests := []struct {
+		next         middleware.Handler
+		expectedCode int
+		expectedBody string
+		expectedLog  string
+		expectedErr  error
+	}{
+		{
+			next:         genErrorHandler(http.StatusOK, nil, "normal"),
+			expectedCode: http.StatusOK,
+			expectedBody: "normal",
+			expectedLog:  "",
+			expectedErr:  nil,
+		},
+		{
+			next:         genErrorHandler(http.StatusMovedPermanently, testErr, ""),
+			expectedCode: http.StatusMovedPermanently,
+			expectedBody: "",
+			expectedLog:  fmt.Sprintf("[ERROR %d %s] %v\n", http.StatusMovedPermanently, "/", testErr),
+			expectedErr:  testErr,
+		},
+		{
+			next:         genErrorHandler(http.StatusBadRequest, nil, ""),
+			expectedCode: 0,
+			expectedBody: fmt.Sprintf("%d %s\n", http.StatusBadRequest,
+				http.StatusText(http.StatusBadRequest)),
+			expectedLog: "",
+			expectedErr: nil,
+		},
+		{
+			next:         genErrorHandler(http.StatusNotFound, nil, ""),
+			expectedCode: 0,
+			expectedBody: content,
+			expectedLog:  "",
+			expectedErr:  nil,
+		},
+		{
+			next:         genErrorHandler(http.StatusForbidden, nil, ""),
+			expectedCode: 0,
+			expectedBody: fmt.Sprintf("%d %s\n", http.StatusForbidden,
+				http.StatusText(http.StatusForbidden)),
+			expectedLog: fmt.Sprintf("HTTP %d could not load error page %s: %v\n",
+				http.StatusForbidden, "not_exist_file", notExistErr),
+			expectedErr: nil,
+		},
+	}
+
+	req, err := http.NewRequest("GET", "/", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for i, test := range tests {
+		em.Next = test.next
+		buf.Reset()
+		rec := httptest.NewRecorder()
+		code, err := em.ServeHTTP(rec, req)
+
+		if err != test.expectedErr {
+			t.Errorf("Test %d: Expected error %v, but got %v",
+				i, test.expectedErr, err)
+		}
+		if code != test.expectedCode {
+			t.Errorf("Test %d: Expected status code %d, but got %d",
+				i, test.expectedCode, code)
+		}
+		if body := rec.Body.String(); body != test.expectedBody {
+			t.Errorf("Test %d: Expected body %q, but got %q",
+				i, test.expectedBody, body)
+		}
+		if log := buf.String(); log != test.expectedLog {
+			t.Errorf("Test %d: Expected log %q, but got %q",
+				i, test.expectedLog, log)
+		}
+	}
+}
+
+func genErrorHandler(status int, err error, body string) middleware.Handler {
+	return middleware.HandlerFunc(func(w http.ResponseWriter, r *http.Request) (int, error) {
+		fmt.Fprint(w, body)
+		return status, err
+	})
+}