Reset EVM in between tests

ethers/providers/jsonrpc.nim

@@ -41,9 +41,9 @@ proc new*(_: type JsonRpcProvider, url=defaultUrl): JsonRpcProvider =
 
 proc send*(provider: JsonRpcProvider,
            call: string,
-           arguments = %(@[])): Future[JsonNode] {.async.} =
+           arguments: seq[JsonNode] = @[]): Future[JsonNode] {.async.} =
   let client = await provider.client
-  return await client.call(call, arguments)
+  return await client.call(call, %arguments)
 
 proc listAccounts*(provider: JsonRpcProvider): Future[seq[Address]] {.async.} =
   let client = await provider.client

testmodule/testContracts.nim

@@ -1,3 +1,4 @@
+import std/json
 import pkg/asynctest
 import pkg/stint
 import pkg/ethers
@@ -15,12 +16,17 @@ suite "Contracts":
 
   var token: TestToken
   var provider: JsonRpcProvider
+  var snapshot: JsonNode
 
   setup:
     provider = JsonRpcProvider.new()
+    snapshot = await provider.send("evm_snapshot")
     let deployment = readDeployment()
     token = TestToken.new(!deployment.address(TestToken), provider)
 
+  teardown:
+    discard await provider.send("evm_revert", @[snapshot])
+
   test "can call view methods":
     let accounts = await provider.listAccounts()
     check (await token.totalSupply()) == 0.u256