tests: move fixtures to dedicated dir

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I9d6ce6a264780f215b1b57d947b5264c6a6a6964

tests/fixtures/indented_string.nix

@@ -0,0 +1,31 @@
+# Test indented strings (multi-line strings with '' delimiters)
+let
+  # Simple indented string
+  simple = ''
+    Hello
+    World
+  '';
+
+  # Indented string with interpolation
+  name = "Nix";
+  greeting = ''
+    Welcome to ${name}!
+    This is indented.
+  '';
+
+  # Escape sequences
+  escapes = ''
+    Literal dollar: ''$
+    Literal quotes: '''
+    Regular text
+  '';
+
+  # Shell script example (common use case)
+  script = ''
+    #!/bin/bash
+    echo "Running script"
+    ls -la
+  '';
+in {
+  inherit simple greeting escapes script;
+}