projects/jaq: add a demo

projects/jaq/default.nix

@@ -26,5 +26,26 @@
     };
   };
 
-  # no service module as this is strictly a program
+  nixos.demo.shell = {
+    module = ./programs/jaq/examples/basic.nix;
+    description = ''
+      A demo shell for testing jaq, a data wrangling tool with formal semantics similar to jq.
+
+      Let's get a basic understanding of jaq's capabilities:
+
+      Here, we can pass in a set or object full of numbers and have jaq add them together.
+
+      $ echo '{"a": 1, "b": 2}' | jaq 'add' # equal to 3
+
+      We can also do more complicated operations like mapping over a list and using conditionals:
+
+      $ echo '[0, 1, 2, 3]' | jaq 'map(.*2) | [.[] | select(. < 5)] | add' # equal to 6
+
+      Finally, jaq will fail if any malformed input is passed
+
+      $ echo "0, 1, 4, " | jaq
+    '';
+
+    tests.basic.module = import ./programs/jaq/tests/shell.nix args;
+  };
 }

projects/jaq/programs/jaq/module.nix

@@ -17,5 +17,10 @@ in
     environment.systemPackages = with pkgs; [
       cfg.package
     ];
+    demo-shell.jaq = {
+      programs = {
+        jaq = cfg.package;
+      };
+    };
   };
 }

projects/jaq/programs/jaq/tests/shell.nix

@@ -0,0 +1,34 @@
+{
+  sources,
+  ...
+}:
+{
+  name = "jaq demo";
+
+  nodes = {
+    machine =
+      { pkgs, ... }:
+      {
+        imports = [
+          sources.modules.ngipkgs
+          sources.modules.programs.jaq
+          sources.examples.jaq.basic
+        ];
+      };
+  };
+
+  testScript =
+    { nodes, ... }:
+    ''
+      start_all()
+
+      # checking if 1 + 2 == 3.
+      machine.succeed('[ "$(echo \'{"a": 1, "b": 2}\' | jaq \'add\')" -eq 3 ]')
+
+      # echo out 0-3, map over them multiplying by 2, keep all elements under 5, add the results up together. Should be 6
+      machine.succeed('[ "$(echo \'[0, 1, 2, 3]\' | jaq \'map(.*2) | [.[] | select(. < 5)] | add\')" -eq 6 ]')
+
+      # fail on malformed input
+      machine.fail('echo "0, 1, 4, " | jaq')
+    '';
+}