Add test for preserve formatting.

Signed-off-by: David Calavera <[email protected]>

src/cargo/ops/cargo_new.rs

@@ -1000,6 +1000,7 @@ fn update_manifest_with_new_member(
         let Some(toml_members) = workspace_document["workspace"]["members"].as_array_mut() else {
             anyhow::bail!("[workspace.members] is not an array");
         };
+
         toml_members.push(relpath);
     } else {
         let mut array = Array::new();

tests/testsuite/cargo_new/add_member_to_workspace/preserve_style/in/Cargo.toml

@@ -0,0 +1,5 @@
+[workspace]
+resolver = "2"
+members = [
+    "crates/bar",
+]

tests/testsuite/cargo_new/add_member_to_workspace/preserve_style/in/src/lib.rs

@@ -0,0 +1,14 @@
+pub fn add(left: usize, right: usize) -> usize {
+    left + right
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() {
+        let result = add(2, 2);
+        assert_eq!(result, 4);
+    }
+}

tests/testsuite/cargo_new/add_member_to_workspace/preserve_style/mod.rs

@@ -0,0 +1,22 @@
+use cargo_test_support::compare::assert_ui;
+use cargo_test_support::curr_dir;
+use cargo_test_support::CargoCommand;
+use cargo_test_support::Project;
+
+#[cargo_test]
+fn case() {
+    let project = Project::from_template(curr_dir!().join("in"));
+    let project_root = project.root();
+    let cwd = &project_root;
+
+    snapbox::cmd::Command::cargo_ui()
+        .arg("new")
+        .args(["crates/foo"])
+        .current_dir(cwd)
+        .assert()
+        .success()
+        .stdout_matches_path(curr_dir!().parent().unwrap().join("stdout.log"))
+        .stderr_matches_path(curr_dir!().parent().unwrap().join("stderr.log"));
+
+    assert_ui().subset_matches(curr_dir!().join("out"), &project_root);
+}

tests/testsuite/cargo_new/add_member_to_workspace/preserve_style/out/Cargo.toml

@@ -0,0 +1,6 @@
+[workspace]
+resolver = "2"
+members = [
+    "crates/bar",
+    "crates/foo",
+]

tests/testsuite/cargo_new/add_member_to_workspace/preserve_style/out/crates/foo/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "foo"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

tests/testsuite/cargo_new/add_member_to_workspace/preserve_style/out/crates/foo/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

tests/testsuite/cargo_new/add_member_to_workspace/preserve_style/out/src/lib.rs

@@ -0,0 +1,14 @@
+pub fn add(left: usize, right: usize) -> usize {
+    left + right
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() {
+        let result = add(2, 2);
+        assert_eq!(result, 4);
+    }
+}