Change key format

key format : ${ENV_PART||defaultValue} or  ${ENV_PART}

config/config_test.go

@@ -0,0 +1,55 @@
+// Copyright 2016 beego Author. All Rights Reserved.
+//
+// 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
+//
+//      http://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 config
+
+import (
+	"os"
+	"testing"
+)
+
+func TestExpandValueEnv(t *testing.T) {
+
+	testCases := []struct {
+		item string
+		want string
+	}{
+		{"", ""},
+		{"$", "$"},
+		{"{", "{"},
+		{"{}", "{}"},
+		{"${}", ""},
+		{"${|}", ""},
+		{"${}", ""},
+		{"${{}}", ""},
+		{"${{||}}", "}"},
+		{"${pwd||}", ""},
+		{"${pwd||}", ""},
+		{"${pwd||}", ""},
+		{"${pwd||}}", "}"},
+		{"${pwd||{{||}}}", "{{||}}"},
+		{"${GOPATH}", os.Getenv("GOPATH")},
+		{"${GOPATH||}", os.Getenv("GOPATH")},
+		{"${GOPATH||root}", os.Getenv("GOPATH")},
+		{"${GOPATH_NOT||root}", "root"},
+		{"${GOPATH_NOT||||root}", "||root"},
+	}
+
+	for _, c := range testCases {
+		if got := ExpandValueEnv(c.item); got != c.want {
+			t.Errorf("expand value error, item %q want %q, got %q", c.item, c.want, got)
+		}
+	}
+
+}