Test that binary runs

Author: MoritzR

.github/workflows/main.yml

@@ -19,6 +19,7 @@ jobs:
     - name: build flake
       run: |
         nix build .#
+        ./result/bin/fints2ledger --help
 
   build:
     name: GHC ${{ matrix.ghc-version }} on ${{ matrix.os }} / build