nu-cli: added tests for file completions (#5232)

* nu-cli: added tests for file completions

* test adding extra sort

* Feature/refactor completion options (#5228)

* Copy completion filter to custom completions

* Remove filter function from completer

This function was a no-op for FileCompletion and CommandCompletion.
Flag- and VariableCompletion just filters with `starts_with` which
happens in both completers anyway and should therefore also be a no-op.
The remaining use case in CustomCompletion was moved into the
CustomCompletion source file.

Filtering should probably happen immediately while fetching completions
to avoid unnecessary memory allocations.

* Add get_sort_by() to Completer trait

* Remove CompletionOptions from Completer::fetch()

* Fix clippy lints

* Apply Completer changes to DotNuCompletion

* add os to $nu based on rust's understanding (#5243)

* add os to $nu based on rust's understanding

* add a few more constants

Co-authored-by: Richard <Tropid@users.noreply.github.com>
Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>

Cargo.lock

@@ -2289,10 +2289,12 @@ dependencies = [
  "miette 4.5.0",
  "nu-ansi-term",
  "nu-color-config",
+ "nu-command",
  "nu-engine",
  "nu-parser",
  "nu-path",
  "nu-protocol",
+ "nu-test-support",
  "nu-utils",
  "reedline",
  "thiserror",

crates/nu-cli/Cargo.toml

@@ -6,6 +6,10 @@ license = "MIT"
 name = "nu-cli"
 version = "0.61.1"
 
+[dev-dependencies]
+nu-test-support = { path="../nu-test-support", version = "0.61.1"  }
+nu-command = { path = "../nu-command", version = "0.61.1" }
+
 [dependencies]
 nu-engine = { path = "../nu-engine", version = "0.61.1"  }
 nu-path = { path = "../nu-path", version = "0.61.1"  }

crates/nu-cli/src/completions/file_completions.rs

@@ -60,6 +60,7 @@ impl Completer for FileCompletion {
 
         // Sort items
         let mut sorted_items = items;
+        sorted_items.sort_by(|a, b| a.value.cmp(&b.value));
         sorted_items.sort_by(|a, b| {
             let a_distance = levenshtein_distance(&prefix_str, &a.value);
             let b_distance = levenshtein_distance(&prefix_str, &b.value);

crates/nu-cli/src/lib.rs

@@ -15,7 +15,7 @@ mod util;
 mod validation;
 
 pub use commands::evaluate_commands;
-pub use completions::NuCompleter;
+pub use completions::{FileCompletion, NuCompleter};
 pub use config_files::eval_config_contents;
 pub use errors::CliError;
 pub use eval_file::evaluate_file;

crates/nu-cli/tests/test_completions.rs

@@ -0,0 +1,84 @@
+use std::path::PathBuf;
+
+use nu_cli::NuCompleter;
+use nu_command::create_default_context;
+use nu_protocol::engine::{EngineState, Stack};
+use nu_test_support::fs;
+use reedline::{Completer, Suggestion};
+const SEP: char = std::path::MAIN_SEPARATOR;
+
+#[test]
+fn file_completions() {
+    // Create a new engine
+    let (dir, dir_str, engine) = new_engine();
+
+    let stack = Stack::new();
+
+    // Instatiate a new completer
+    let mut completer = NuCompleter::new(std::sync::Arc::new(engine), stack.clone());
+
+    // Test completions for the current folder
+    let target_dir = format!("cd {}", dir_str);
+    let suggestions = completer.complete(&target_dir, target_dir.len());
+
+    // Create the expected values
+    let expected_paths: Vec<String> = vec![
+        file(dir.clone().join("nushell")),
+        folder(dir.clone().join("test_a")),
+        folder(dir.clone().join("test_b")),
+        folder(dir.clone().join("another")),
+        file(dir.clone().join(".hidden_file")),
+        folder(dir.clone().join(".hidden_folder")),
+    ];
+
+    // Match the results
+    match_suggestions(expected_paths, suggestions);
+
+    // Test completions for the completions/another folder
+    let target_dir = format!("cd {}", folder(dir.clone().join("another")));
+    let suggestions = completer.complete(&target_dir, target_dir.len());
+
+    // Create the expected values
+    let expected_paths: Vec<String> = vec![file(dir.clone().join("another").join("newfile"))];
+
+    // Match the results
+    match_suggestions(expected_paths, suggestions);
+}
+
+// creates a new engine with the current path into the completions fixtures folder
+fn new_engine() -> (PathBuf, String, EngineState) {
+    // Target folder inside assets
+    let dir = fs::fixtures().join("completions");
+    let mut dir_str = dir
+        .clone()
+        .into_os_string()
+        .into_string()
+        .unwrap_or("".to_string());
+    dir_str.push(SEP);
+
+    // Create a default engine
+    (dir.clone(), dir_str, create_default_context(dir))
+}
+
+// match a list of suggestions with the expected values
+fn match_suggestions(expected: Vec<String>, suggestions: Vec<Suggestion>) {
+    expected.iter().zip(suggestions).for_each(|it| {
+        assert_eq!(it.0, &it.1.value);
+    });
+}
+
+// append the separator to the converted path
+fn folder(path: PathBuf) -> String {
+    let mut converted_path = file(path);
+    converted_path.push(SEP);
+
+    converted_path
+}
+
+// convert a given path to string
+fn file(path: PathBuf) -> String {
+    path.clone()
+        .into_os_string()
+        .into_string()
+        .unwrap_or("".to_string())
+}

crates/nu-test-support/src/fs.rs

@@ -258,7 +258,7 @@ pub fn binaries() -> PathBuf {
 }
 
 pub fn fixtures() -> PathBuf {
-    root().join("tests/fixtures")
+    root().join("tests").join("fixtures")
 }
 
 pub fn assets() -> PathBuf {