fastfetch: add module

PR #5363

tests/modules/programs/fastfetch/basic-configuration.nix

@@ -0,0 +1,39 @@
+{
+  programs.fastfetch = {
+    enable = true;
+    settings = {
+      logo = {
+        source = "nixos_small";
+        padding = { right = 1; };
+      };
+      display = {
+        binaryPrefix = "si";
+        color = "blue";
+        separator = "  ";
+      };
+      modules = [
+        {
+          type = "datetime";
+          key = "Date";
+          format = "{1}-{3}-{11}";
+        }
+        {
+          type = "datetime";
+          key = "Time";
+          format = "{14}:{17}:{20}";
+        }
+        "break"
+        "player"
+        "media"
+      ];
+    };
+  };
+
+  test.stubs.fastfetch = { };
+
+  nmt.script = let configFile = "home-files/.config/fastfetch/config.jsonc";
+  in ''
+    assertFileExists "${configFile}"
+    assertFileContent "${configFile}" ${./basic-configuration.jsonc}
+  '';
+}