initialize spec macro and standards

Signed-off-by: Onur Özkan <work@onurozkan.dev>

kaptan-spec/tests/spec_macro.rs

@@ -0,0 +1,11 @@
+#[test]
+fn accepts_existing_sidecar_spec() {
+    let tests = trybuild::TestCases::new();
+    tests.pass("tests/ui/flight_core_contract.rs");
+}
+
+#[test]
+fn rejects_missing_sidecar_spec() {
+    let tests = trybuild::TestCases::new();
+    tests.compile_fail("tests/ui/fail_missing_sidecar.rs");
+}