ledger: add structural settings option (#3661)

tests/modules/programs/ledger/default.nix

@@ -0,0 +1 @@
+{ ledger = ./ledger.nix; }

tests/modules/programs/ledger/ledger.nix

@@ -0,0 +1,35 @@
+{ ... }:
+
+{
+  programs.ledger = {
+    enable = true;
+    settings = {
+      sort = "date";
+      strict = true;
+      pedantic = true;
+      leeway = 30;
+      date-format = "%Y-%m-%d";
+      file = [
+        "~/finances/journal.ledger"
+        "~/finances/assets.ledger"
+        "~/finances/income.ledger"
+      ];
+    };
+  };
+
+  test.stubs.ledger = { };
+
+  nmt.script = ''
+    assertFileContent home-files/.config/ledger/ledgerrc \
+    ${builtins.toFile "ledger-expected-settings" ''
+      --date-format %Y-%m-%d
+      --file ~/finances/journal.ledger
+      --file ~/finances/assets.ledger
+      --file ~/finances/income.ledger
+      --leeway 30
+      --pedantic
+      --sort date
+      --strict
+    ''}
+  '';
+}