Add ContextMap method to LoggedEntry which returns fields as a map (u…

…ber-go#490)

Tests often care about specific fields, or want fields without worrying
about order, or marshalling objects etc. It makes more sense for tests
to compare a fields `map[string]interface{}` rather than `[]zap.Field`

zaptest/observer/logged_entry.go

@@ -0,0 +1,39 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package observer
+
+import "go.uber.org/zap/zapcore"
+
+// An LoggedEntry is an encoding-agnostic representation of a log message.
+// Field availability is context dependant.
+type LoggedEntry struct {
+	zapcore.Entry
+	Context []zapcore.Field
+}
+
+// ContextMap returns a map for all fields in Context.
+func (e LoggedEntry) ContextMap() map[string]interface{} {
+	encoder := zapcore.NewMapObjectEncoder()
+	for _, f := range e.Context {
+		f.AddTo(encoder)
+	}
+	return encoder.Fields
+}

zaptest/observer/logged_entry_test.go

@@ -0,0 +1,88 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package observer
+
+import (
+	"testing"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLoggedEntryContextMap(t *testing.T) {
+	tests := []struct {
+		msg    string
+		fields []zapcore.Field
+		want   map[string]interface{}
+	}{
+		{
+			msg:    "no fields",
+			fields: nil,
+			want:   map[string]interface{}{},
+		},
+		{
+			msg: "simple",
+			fields: []zapcore.Field{
+				zap.String("k1", "v"),
+				zap.Int64("k2", 10),
+			},
+			want: map[string]interface{}{
+				"k1": "v",
+				"k2": int64(10),
+			},
+		},
+		{
+			msg: "overwrite",
+			fields: []zapcore.Field{
+				zap.String("k1", "v1"),
+				zap.String("k1", "v2"),
+			},
+			want: map[string]interface{}{
+				"k1": "v2",
+			},
+		},
+		{
+			msg: "nested",
+			fields: []zapcore.Field{
+				zap.String("k1", "v1"),
+				zap.Namespace("nested"),
+				zap.String("k2", "v2"),
+			},
+			want: map[string]interface{}{
+				"k1": "v1",
+				"nested": map[string]interface{}{
+					"k2": "v2",
+				},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.msg, func(t *testing.T) {
+			entry := LoggedEntry{
+				Context: tt.fields,
+			}
+			assert.Equal(t, tt.want, entry.ContextMap())
+		})
+	}
+}

zaptest/observer/observer.go

@@ -32,13 +32,6 @@ import (
 	"go.uber.org/zap/zapcore"
 )
 
-// An LoggedEntry is an encoding-agnostic representation of a log message.
-// Field availability is context dependant.
-type LoggedEntry struct {
-	zapcore.Entry
-	Context []zapcore.Field
-}
-
 // ObservedLogs is a concurrency-safe, ordered collection of observed logs.
 type ObservedLogs struct {
 	mu   sync.RWMutex