Support tests that need a terminal emulator

Cargo.lock

@@ -56,6 +56,30 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "alacritty_terminal"
+version = "0.24.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db5ad9e2d4c1f7e17fccec9493eeb4e9c1f00e1167519d3940272b708ed8a069"
+dependencies = [
+ "base64 0.22.1",
+ "bitflags 2.5.0",
+ "home",
+ "libc",
+ "log",
+ "miow",
+ "parking_lot",
+ "piper",
+ "polling",
+ "regex-automata",
+ "rustix-openpty",
+ "serde",
+ "signal-hook",
+ "unicode-width",
+ "vte 0.13.0",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "alloc-no-stdlib"
 version = "2.0.4"
@@ -297,6 +321,12 @@ version = "0.15.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9ae037714f313c1353189ead58ef9eec30a8e8dc101b2622d461418fd59e28a9"
 
+[[package]]
+name = "atomic-waker"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1505bd5d3d116872e7271a6d4e16d81d0c8570876c8de68093a09ac269d8aac0"
+
 [[package]]
 name = "autocfg"
 version = "1.2.0"
@@ -888,6 +918,15 @@ dependencies = [
  "static_assertions",
 ]
 
+[[package]]
+name = "concurrent-queue"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4ca0197aee26d1ae37445ee532fefce43251d24cc7c166799f4d46817f1d3973"
+dependencies = [
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "console"
 version = "0.15.8"
@@ -1129,6 +1168,12 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "cursor-icon"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96a6ac251f4a2aca6b3f91340350eab87ae57c3f127ffeb585e92bd336717991"
+
 [[package]]
 name = "deranged"
 version = "0.3.11"
@@ -2632,6 +2677,15 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "miow"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "359f76430b20a79f9e20e115b3428614e654f04fab314482fc0fda0ebd3c6044"
+dependencies = [
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "mockito"
 version = "1.4.0"
@@ -2772,6 +2826,7 @@ dependencies = [
 name = "nu"
 version = "0.94.1"
 dependencies = [
+ "alacritty_terminal",
  "assert_cmd",
  "crossterm",
  "ctrlc",
@@ -3304,6 +3359,7 @@ dependencies = [
 name = "nu-test-support"
 version = "0.94.1"
 dependencies = [
+ "alacritty_terminal",
  "nu-glob",
  "nu-path",
  "nu-utils",
@@ -3981,6 +4037,17 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
 
+[[package]]
+name = "piper"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "464db0c665917b13ebb5d453ccdec4add5658ee1adc7affc7677615356a8afaf"
+dependencies = [
+ "atomic-waker",
+ "fastrand",
+ "futures-io",
+]
+
 [[package]]
 name = "pkg-config"
 version = "0.3.30"
@@ -4417,6 +4484,21 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "polling"
+version = "3.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "645493cf344456ef24219d02a768cf1fb92ddf8c92161679ae3d91b91a637be3"
+dependencies = [
+ "cfg-if",
+ "concurrent-queue",
+ "hermit-abi",
+ "pin-project-lite",
+ "rustix",
+ "tracing",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "pori"
 version = "0.0.0"
@@ -5123,11 +5205,23 @@ checksum = "70dc5ec042f7a43c4a73241207cecc9873a06d45debb38b329f8541d85c2730f"
 dependencies = [
  "bitflags 2.5.0",
  "errno",
+ "itoa",
  "libc",
  "linux-raw-sys",
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "rustix-openpty"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a25c3aad9fc1424eb82c88087789a7d938e1829724f3e4043163baf0d13cfc12"
+dependencies = [
+ "errno",
+ "libc",
+ "rustix",
+]
+
 [[package]]
 name = "rustversion"
 version = "1.0.15"
@@ -6543,6 +6637,20 @@ dependencies = [
  "vte_generate_state_changes",
 ]
 
+[[package]]
+name = "vte"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "40eb22ae96f050e0c0d6f7ce43feeae26c348fc4dea56928ca81537cfaa6188b"
+dependencies = [
+ "bitflags 2.5.0",
+ "cursor-icon",
+ "log",
+ "serde",
+ "utf8parse",
+ "vte_generate_state_changes",
+]
+
 [[package]]
 name = "vte_generate_state_changes"
 version = "0.1.1"

Cargo.toml

@@ -61,6 +61,7 @@ members = [
 ]
 
 [workspace.dependencies]
+alacritty_terminal = "0.24"
 alphanumeric-sort = "1.5"
 ansi-str = "0.8"
 anyhow = "1.0.82"
@@ -221,6 +222,7 @@ nix = { workspace = true, default-features = false, features = [
 nu-test-support = { path = "./crates/nu-test-support", version = "0.94.1" }
 nu-plugin-protocol = { path = "./crates/nu-plugin-protocol", version = "0.94.1" }
 nu-plugin-core = { path = "./crates/nu-plugin-core", version = "0.94.1" }
+alacritty_terminal = { workspace = true }
 assert_cmd = "2.0"
 dirs-next = { workspace = true }
 tango-bench = "0.5"
@@ -305,4 +307,4 @@ bench = false
 # Run individual benchmarks like `cargo bench -- <regex>` e.g. `cargo bench -- parse`
 [[bench]]
 name = "benchmarks"
-harness = false
+harness = false

crates/nu-test-support/Cargo.toml

@@ -18,4 +18,5 @@ nu-utils = { path = "../nu-utils", version = "0.94.1" }
 
 num-format = { workspace = true }
 which = { workspace = true }
-tempfile = { workspace = true }
+tempfile = { workspace = true }
+alacritty_terminal = { workspace = true }

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

@@ -3,6 +3,7 @@ pub mod fs;
 pub mod locale_override;
 pub mod macros;
 pub mod playground;
+pub mod terminal;
 use std::process::ExitStatus;
 
 // Needs to be reexported for `nu!` macro

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

@@ -0,0 +1,126 @@
+//! Helper functions for tests that requires a terminal emulator.
+
+use alacritty_terminal::{
+    event::{Event, EventListener, WindowSize},
+    grid::Indexed,
+    term::{test::TermSize, Config},
+    tty::{self, EventedReadWrite, Options, Pty, Shell},
+    vte::ansi::{Processor, StdSyncHandler},
+    Term,
+};
+use std::{
+    collections::HashMap,
+    io::{ErrorKind, Read, Write},
+    path::PathBuf,
+    sync::mpsc,
+    time::Duration,
+};
+
+pub struct EventProxy(mpsc::Sender<Event>);
+
+impl EventListener for EventProxy {
+    fn send_event(&self, event: Event) {
+        let _ = self.0.send(event);
+    }
+}
+
+/// Creates a 24x80 terminal with default configurations. Returns the terminal
+/// and a `mpsc::Receiver` that receives terminal events.
+pub fn default_terminal() -> (Term<EventProxy>, mpsc::Receiver<Event>) {
+    let config = Config::default();
+    let size = TermSize {
+        screen_lines: 24,
+        columns: 80,
+    };
+    let (tx, rx) = mpsc::channel();
+    (Term::new(config, &size, EventProxy(tx)), rx)
+}
+
+/// Creates a PTY and connect the slave end to a Nushell process. If `pwd` is
+/// None, the Nushell process will inherit PWD from the current process.
+pub fn pty_with_nushell(args: Vec<String>, pwd: Option<PathBuf>) -> Pty {
+    let executable = crate::fs::executable_path().to_string_lossy().to_string();
+    let options = Options {
+        shell: Some(Shell::new(executable, args)),
+        working_directory: pwd,
+        hold: false,
+        env: HashMap::new(),
+    };
+    let window_size = WindowSize {
+        num_lines: 24,
+        num_cols: 80,
+        cell_width: 0,
+        cell_height: 0,
+    };
+    tty::new(&options, window_size, 0).unwrap()
+}
+
+/// Reads from `pty` until no more data is available. Will periodically call
+/// `event_handler` to handle terminal events.
+pub fn read_to_end<T: EventListener>(
+    terminal: &mut Term<T>,
+    pty: &mut Pty,
+    events: &mut mpsc::Receiver<Event>,
+    mut event_handler: impl FnMut(&mut Term<T>, &mut Pty, Event),
+) {
+    let mut parser: Processor<StdSyncHandler> = Processor::new();
+    loop {
+        // Read from the PTY.
+        let mut buf = [0; 512];
+        match pty.reader().read(&mut buf) {
+            Ok(n) => {
+                if n == 0 {
+                    return;
+                } else {
+                    // Update the terminal state.
+                    for byte in &buf[..n] {
+                        parser.advance(terminal, *byte);
+                    }
+
+                    // Handle terminal events.
+                    while let Ok(event) = events.try_recv() {
+                        event_handler(terminal, pty, event);
+                    }
+
+                    // Poll again after 100ms. The delay is necessary so that
+                    // the child process can respond to any new data we might
+                    // have sent in the event handler.
+                    std::thread::sleep(Duration::from_millis(100));
+                }
+            }
+            Err(err) => {
+                if let ErrorKind::Interrupted = err.kind() {
+                    // retry
+                } else {
+                    return;
+                }
+            }
+        }
+    }
+}
+
+/// An event handler that only responds to `Event::PtyWrite`. This is the
+/// minimum amount of event handling you need to get Nushell working.
+pub fn pty_write_handler<T: EventListener>(_terminal: &mut Term<T>, pty: &mut Pty, event: Event) {
+    if let Event::PtyWrite(text) = event {
+        pty.writer().write_all(text.as_bytes()).unwrap();
+    }
+}
+
+/// Extracts the current cursor position.
+pub fn extract_cursor<T>(terminal: &Term<T>) -> (usize, usize) {
+    let cursor = terminal.grid().cursor.point;
+    (cursor.line.0 as usize, cursor.column.0 as usize)
+}
+
+/// Extracts all visible text, ignoring text styles.
+pub fn extract_text<T>(terminal: &Term<T>) -> Vec<String> {
+    let mut text: Vec<String> = vec![];
+    for Indexed { point, cell } in terminal.grid().display_iter() {
+        if point.column == 0 {
+            text.push(String::new());
+        }
+        text.last_mut().unwrap().push(cell.c);
+    }
+    text
+}