Move dummy service implementations into their own package.

go/src/infra/gae/libs/gae/mathrand_test.go

Index: go/src/infra/gae/libs/gae/mathrand_test.go
diff --git a/go/src/infra/gae/libs/gae/mathrand_test.go b/go/src/infra/gae/libs/gae/mathrand_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..4fea05ff1fdc89ccfe6dbfc8409b1551931d4b34
--- /dev/null
+++ b/go/src/infra/gae/libs/gae/mathrand_test.go
@@ -0,0 +1,50 @@
+// 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 gae
+
+import (
+	"math/rand"
+	"testing"
+	"time"
+
+	"golang.org/x/net/context"
+
+	"github.com/luci/luci-go/common/clock/testclock"
+
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestMathRand(t *testing.T) {
+	t.Parallel()
+
+	Convey("test mathrand", t, func() {
+		now := time.Date(2015, 1, 1, 0, 0, 0, 0, time.UTC)
+		c, _ := testclock.UseTime(context.Background(), now)
+
+		// Note that the non-randomness below is because time is fixed at the
+		// top of the outer test function. Normally it would evolve with time.
+		Convey("unset", func() {
+			r := rand.New(rand.NewSource(now.UnixNano()))
+			i := r.Int()
+			So(GetMathRand(c).Int(), ShouldEqual, i)
+			So(GetMathRand(c).Int(), ShouldEqual, i)
+		})
+
+		Convey("set persistance", func() {
+			c = SetMathRand(c, rand.New(rand.NewSource(now.UnixNano())))
+			r := rand.New(rand.NewSource(now.UnixNano()))
+			So(GetMathRand(c).Int(), ShouldEqual, r.Int())
+			So(GetMathRand(c).Int(), ShouldEqual, r.Int())
+		})
+
+		Convey("nil set", func() {
+			c = SetMathRand(c, nil)
+			r := rand.New(rand.NewSource(now.UnixNano()))
+			i := r.Int()
+			So(GetMathRand(c).Int(), ShouldEqual, i)
+			So(GetMathRand(c).Int(), ShouldEqual, i)
+		})
+	})
+}