Refactor a bit.

service/rawdatastore/context_test.go

Index: service/rawdatastore/context_test.go
diff --git a/service/rawdatastore/context_test.go b/service/rawdatastore/context_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..5c4db01b705ba91afe113873b1bb94457330b13b
--- /dev/null
+++ b/service/rawdatastore/context_test.go
@@ -0,0 +1,52 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package rawdatastore
+
+import (
+	"errors"
+	"testing"
+
+	. "github.com/smartystreets/goconvey/convey"
+	"golang.org/x/net/context"
+)
+
+type fakeService struct{ Interface }
+
+type fakeFilt struct{ Interface }
+
+func (fakeFilt) Count(Query) (int, error) {
+	return 0, errors.New("wow")
+}
+
+func TestServices(t *testing.T) {
+	t.Parallel()
+
+	Convey("Test service interfaces", t, func() {
+		c := context.Background()
+		Convey("without adding anything", func() {
+			So(Get(c), ShouldBeNil)
+		})
+
+		Convey("adding a basic implementation", func() {
+			c = Set(c, fakeService{})
+
+			Convey("lets you pull them back out", func() {
+				So(Get(c), ShouldResemble, fakeService{})
+			})
+
+			Convey("and lets you add filters", func() {
+				c = AddFilters(c, func(ic context.Context, rds Interface) Interface {
+					return fakeFilt{rds}
+				})
+
+				_, err := Get(c).Count(nil)
+				So(err.Error(), ShouldEqual, "wow")
+			})
+		})
+		Convey("adding zero filters does nothing", func() {
+			So(AddFilters(c), ShouldEqual, c)
+		})
+	})
+}