First stab at mock client

client/mock/context.go

@@ -0,0 +1,16 @@
+package mock
+
+import (
+	"golang.org/x/net/context"
+)
+
+type responseKey struct{}
+
+func fromContext(ctx context.Context) (map[string][]MockResponse, bool) {
+	r, ok := ctx.Value(responseKey{}).(map[string][]MockResponse)
+	return r, ok
+}
+
+func newContext(ctx context.Context, r map[string][]MockResponse) context.Context {
+	return context.WithValue(ctx, responseKey{}, r)
+}