From 83a38341624582e45ee4d2d1f81ea8d3435a74dd Mon Sep 17 00:00:00 2001
From: Prashant Varanasi <prashant@uber.com>
Date: Tue, 15 Aug 2017 16:25:49 -0700
Subject: [PATCH] Add function to convert []Field to map[string]interface{}

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/fields.go      | 32 ++++++++++++
 zaptest/observer/fields_test.go | 86 +++++++++++++++++++++++++++++++++
 2 files changed, 118 insertions(+)
 create mode 100644 zaptest/observer/fields.go
 create mode 100644 zaptest/observer/fields_test.go

diff --git a/zaptest/observer/fields.go b/zaptest/observer/fields.go
new file mode 100644
index 000000000..2db510678
--- /dev/null
+++ b/zaptest/observer/fields.go
@@ -0,0 +1,32 @@
+// 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"
+
+// FieldsMap takes a list of fields and converts it to a map.
+func FieldsMap(fields []zapcore.Field) map[string]interface{} {
+	encoder := zapcore.NewMapObjectEncoder()
+	for _, f := range fields {
+		f.AddTo(encoder)
+	}
+	return encoder.Fields
+}
diff --git a/zaptest/observer/fields_test.go b/zaptest/observer/fields_test.go
new file mode 100644
index 000000000..f80768617
--- /dev/null
+++ b/zaptest/observer/fields_test.go
@@ -0,0 +1,86 @@
+// 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 TestFieldsMap(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) {
+			assert.Equal(t, tt.want, FieldsMap(tt.fields))
+
+		})
+	}
+}