chore(tvix/nix_cli): build with tests

only run test_nix_store_add() when the feature integration_tests is
enabled.

Change-Id: I600f08ecaefe1ce77651ae07a58d7987107ab969
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6084
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

tvix/nix_cli/src/bin/nix-store.rs

@@ -80,6 +80,7 @@ mod integration_tests {
     }
 
     #[test]
+    #[cfg_attr(not(feature = "integration_tests"), ignore)]
     fn test_nix_store_add() {
         let file_content = "I am a copied file";
         let mut tempfile = tempfile::NamedTempFile::new().expect("cannot create temp file");