fix eth_getCode and add test cases (#303)

* test: add eth_call cases

* test: add eth_getCode cases

* fix: change eth_getCode not found response to 0x

e2e/test/e2e-json-rpc.test.ts

@@ -14,6 +14,11 @@ describe("JSON-RPC", () => {
                 (await sendExpect("hardhat_reset", [])).eq(true);
             }
         });
+
+        it("Code for non-existent contract is 0x", async () => {
+            const addressWithNothingDeployed = ALICE.address;
+            (await sendExpect("eth_getCode", [addressWithNothingDeployed, "latest"])).eq("0x");
+        });
     });
 
     describe("Metadata", () => {

e2e/test/e2e-tx-serial-contract.test.ts

@@ -25,10 +25,42 @@ describe("Transaction: serial TestContractBalances", () => {
     it("Resets blockchain", async () => {
         await sendReset();
     });
+
     it("Contract is deployed", async () => {
         _contract = await deployTestContractBalances();
     });
 
+    it("Eth_getCode is not null for deployed contract", async () => {
+        const deployedCode = await send("eth_getCode", [_contract.target, "latest"]);
+
+        expect(deployedCode).not.eq("0x");
+    });
+
+    it("Eth_call works on read function", async () => {
+        // prepare transaction object
+        const data = _contract.interface.encodeFunctionData("get", [CHARLIE.address])
+        const to = _contract.target;
+        const from = CHARLIE.address;
+        const transaction = {from: from, to: to, data: data};
+
+        const currentCharlieBalance = await send("eth_call", [transaction, "latest"]);
+        const expectedCharlieBalance = toPaddedHex(0, 32);
+
+        expect(currentCharlieBalance).eq(expectedCharlieBalance);
+    });
+
+    it("Eth_call works on read function without from field", async () => {
+        // prepare transaction object
+        const data = _contract.interface.encodeFunctionData("get", [CHARLIE.address])
+        const to = _contract.target;
+        const transaction = {to: to, data: data};
+
+        const currentCharlieBalance = await send("eth_call", [transaction, "latest"]);
+        const expectedCharlieBalance = toPaddedHex(0, 32);
+
+        expect(currentCharlieBalance).eq(expectedCharlieBalance);
+    });
+
     it("Performs add and sub", async () => {
         _block = await sendGetBlockNumber();
 

src/eth/rpc/rpc_server.rs

@@ -339,7 +339,7 @@ async fn eth_get_code(params: Params<'_>, ctx: Arc<RpcContext>) -> anyhow::Resul
     let point_in_time = ctx.storage.translate_to_point_in_time(&block_selection).await?;
     let account = ctx.storage.read_account(&address, &point_in_time).await?;
 
-    Ok(account.bytecode.map(hex_data).unwrap_or_else(hex_zero))
+    Ok(account.bytecode.map(hex_data).unwrap_or_else(hex_null))
 }
 
 // Subscription
@@ -403,3 +403,7 @@ fn hex_num_zero_padded(value: impl Into<U256>) -> String {
 fn hex_zero() -> String {
     "0x0".to_owned()
 }
+
+fn hex_null() -> String {
+    "0x".to_owned()
+}