Explicity contract encoding tests (non e2e) (#1040)

packages/api-contract/src/Abi.spec.ts

@@ -83,6 +83,25 @@ describe('Abi', () => {
         'Vec<(u32,u64)>'
       );
     });
+
+    describe('messages', () => {
+      it('fails when invalid args are supplied', () => {
+        expect(
+          () => abi.messages.primitive(false)
+        ).toThrow(/Expected 2 arguments to contract messages.primitive, found 1/);
+      });
+
+      it('encodes primitives correctly', () => {
+        expect(
+          abi.messages.primitive(true, 0x12345678)
+        ).toEqual(new Uint8Array([
+          9 << 2, // total length (4 + 1 + 4)
+          0x67, 0x2b, 0, 0, // 11111 -> hex (LE)
+          1, // true
+          0x78, 0x56, 0x34, 0x12 // u32
+        ]));
+      });
+    });
   });
 
   describe('erc20', () => {

packages/api-contract/test/abi/types.json

@@ -6,7 +6,7 @@
   "messages": [
     {
       "name": "primitive",
-      "selector": 1111,
+      "selector": 11111,
       "mutates": true,
       "args": [
         {