1 files changed, 78 insertions, 0 deletions
diff --git a/packages/taler-util/src/codec.test.ts b/packages/taler-util/src/codec.test.ts
new file mode 100644
index 000000000..f8f4c797c
--- /dev/null
+++ b/packages/taler-util/src/codec.test.ts
@@ -0,0 +1,78 @@
+/*
+ This file is part of GNU Taler
+ (C) 2018-2019 GNUnet e.V.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+/**
+ * Type-safe codecs for converting from/to JSON.
+ */
+
+import test from "ava";
+import {
+  Codec,
+  buildCodecForObject,
+  codecForConstString,
+  codecForString,
+  buildCodecForUnion,
+} from "./codec";
+
+interface MyObj {
+  foo: string;
+}
+
+interface AltOne {
+  type: "one";
+  foo: string;
+}
+
+interface AltTwo {
+  type: "two";
+  bar: string;
+}
+
+type MyUnion = AltOne | AltTwo;
+
+test("basic codec", (t) => {
+  const myObjCodec = buildCodecForObject<MyObj>()
+    .property("foo", codecForString())
+    .build("MyObj");
+  const res = myObjCodec.decode({ foo: "hello" });
+  t.assert(res.foo === "hello");
+
+  t.throws(() => {
+    myObjCodec.decode({ foo: 123 });
+  });
+});
+
+test("union", (t) => {
+  const altOneCodec: Codec<AltOne> = buildCodecForObject<AltOne>()
+    .property("type", codecForConstString("one"))
+    .property("foo", codecForString())
+    .build("AltOne");
+  const altTwoCodec: Codec<AltTwo> = buildCodecForObject<AltTwo>()
+    .property("type", codecForConstString("two"))
+    .property("bar", codecForString())
+    .build("AltTwo");
+  const myUnionCodec: Codec<MyUnion> = buildCodecForUnion<MyUnion>()
+    .discriminateOn("type")
+    .alternative("one", altOneCodec)
+    .alternative("two", altTwoCodec)
+    .build<MyUnion>("MyUnion");
+
+  const res = myUnionCodec.decode({ type: "one", foo: "bla" });
+  t.is(res.type, "one");
+  if (res.type == "one") {
+    t.is(res.foo, "bla");
+  }
+});