Swap contract module test - initial step (#369)

* Basic pwd shelling out script

* Get balance string from running node

* Add comment re manual test

* Add TODOs

tests/all_tests_v2.nim

@@ -13,3 +13,7 @@ import
   ./v2/test_peer_manager,
   ./v2/test_web3, # TODO  remove it when rln-relay tests get finalized
   ./v2/test_waku_rln_relay
+
+# TODO Only enable this once swap module is integrated more nicely as a dependency, i.e. as submodule with CI etc
+# For PoC execute it manually and run separate module here: https://github.com/vacp2p/swap-contracts-module
+#  ./v2/test_waku_swap_contracts

tests/v2/test_waku_swap_contracts.nim

@@ -0,0 +1,27 @@
+ # Tests of Swap contracts via external module
+ #
+import
+  std/[unittest, options, tables, sets, osproc, strutils, strformat],
+  ../test_helpers, ./utils
+
+procSuite "Basic balance test":
+  test "Get pwd of swap module":
+    let (output, errC) = osproc.execCmdEx("(cd ../swap-contracts-module && pwd)")
+    echo output
+
+    check:
+      contains(output, "swap-contracts-module")
+
+  test "Get balance from running node":
+    # NOTE: This corresponds to the first default account in Hardhat
+    let taskString = "npx hardhat balance --account 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266"
+    let cmdString = "cd ../swap-contracts-module; " & &"{taskString}"
+    echo cmdString
+    let (output, errC) = osproc.execCmdEx(cmdString)
+    echo output
+
+    check:
+      contains(output, "ETH")
+
+  # TODO Setup more tasks in Swap module for e2e PoC
+  # TODO Use basic JSON interface instead of strings for basic IO