test(add): Show quoting behavior for --target

Author: epage

tests/testsuite/cargo_add/target_cfg/mod.rs

@@ -28,7 +28,7 @@ fn case() {
 
     snapbox::cmd::Command::cargo_ui()
         .arg("add")
-        .arg_line("my-package1 my-package2 --target cfg(unix)")
+        .arg_line("my-package1 my-package2 --target 'cfg(target_os=\"linux\")'")
         .current_dir(cwd)
         .assert()
         .success()

tests/testsuite/cargo_add/target_cfg/out/Cargo.toml

@@ -5,6 +5,6 @@ name = "cargo-list-test-fixture"
 version = "0.0.0"
 edition = "2015"
 
-[target."cfg(unix)".dependencies]
+[target."cfg(target_os=/"linux/")".dependencies]
 my-package1 = "99999.0.0"
 my-package2 = "99999.0.0"