Add LSP-assisted terminal E2E coverage

src/main.zig

@@ -127,7 +127,18 @@ pub fn main(init: std.process.Init) !u8 {
         }
     }
 
-    const command = if (first_arg) |arg|
+    var e2e_prelude_path: ?[]const u8 = null;
+    var open_arg = first_arg;
+    if (first_arg) |arg| {
+        if (std.mem.eql(u8, arg, "--e2e-prelude-file")) {
+            e2e_prelude_path = args.next() orelse {
+                try stderr.writeStreamingAll(init.io, "mim: --e2e-prelude-file requires a path\n");
+                return 64;
+            };
+            open_arg = args.next();
+        }
+    }
+    const command = if (open_arg) |arg|
         parseArgs(&.{ "mim", arg })
     else
         parseArgs(&.{"mim"});
@@ -135,7 +146,7 @@ pub fn main(init: std.process.Init) !u8 {
     switch (command) {
         .help => try stdout.writeStreamingAll(init.io, help_text),
         .version => try stdout.writeStreamingAll(init.io, versionText()),
-        .open => |path| try openLocalEditor(allocator, init.io, stdout, stderr, path),
+        .open => |path| try openLocalEditor(allocator, init.io, stdout, stderr, path, e2e_prelude_path),
     }
 
     return 0;
@@ -147,6 +158,7 @@ fn openLocalEditor(
     stdout: std.Io.File,
     stderr: std.Io.File,
     path: []const u8,
+    e2e_prelude_path: ?[]const u8,
 ) !void {
     var client = try tui.Client.init(allocator, .{ .width = 80, .height = 22 });
     defer client.deinit();
@@ -167,7 +179,7 @@ fn openLocalEditor(
                 const bytes = std.Io.Dir.cwd().readFileAlloc(io, path, allocator, .limited(diagnostics.max_file_bytes)) catch |err| switch (err) {
                     error.StreamTooLong => {
                         try client.handleTraceLine("open diagnostic:file_too_large");
-                        return runLocalEditor(allocator, io, stdout, stderr, &client, path, false);
+                        return runLocalEditor(allocator, io, stdout, stderr, &client, path, false, e2e_prelude_path);
                     },
                     else => return err,
                 };
@@ -182,7 +194,7 @@ fn openLocalEditor(
         try client.handleTraceLine("open ");
     }
 
-    try runLocalEditor(allocator, io, stdout, stderr, &client, path, stat != null and stat.?.kind == .directory);
+    try runLocalEditor(allocator, io, stdout, stderr, &client, path, stat != null and stat.?.kind == .directory, e2e_prelude_path);
 }
 
 fn seedDirectoryRepo(allocator: std.mem.Allocator, io: std.Io, client: *tui.Client, path: []const u8) !void {
@@ -227,6 +239,7 @@ fn runLocalEditor(
     client: *tui.Client,
     path: []const u8,
     is_dir: bool,
+    e2e_prelude_path: ?[]const u8,
 ) !void {
     const stdin_file = std.Io.File.stdin();
     const interactive = stdin_file.isTty(io) catch false;
@@ -236,6 +249,13 @@ fn runLocalEditor(
     var last_client_saved: ?[]u8 = null;
     defer if (last_client_saved) |bytes| allocator.free(bytes);
 
+    if (e2e_prelude_path) |prelude_path| {
+        const prelude = try std.Io.Dir.cwd().readFileAlloc(io, prelude_path, allocator, .limited(64 * 1024));
+        defer allocator.free(prelude);
+        var lines = std.mem.splitScalar(u8, prelude, '\n');
+        while (lines.next()) |line| if (line.len != 0) try client.handleTraceLine(line);
+    }
+
     if (!interactive) {
         try renderLocalFrame(allocator, io, stdout, client, path, is_dir, false);
         return;

tools/TERMINAL_E2E.md

@@ -31,6 +31,9 @@ Artifact roles:
   while still recording all raw bytes sent.
 - `saved-files.tsv`: per-file hashes/byte counts for scenarios that assert more
   than the launched file, such as multi-file coding workflows.
+- `e2e-prelude.trace` (scenario temp dir only when needed): harness-only trace
+  lines consumed before raw-mode input to seed deterministic provider fixtures;
+  this is not a runtime config surface.
 - `raw.bin`: exact PTY bytes for low-level debugging.
 
 Golden policy:

tools/terminal_e2e.py

@@ -45,6 +45,7 @@ class Scenario:
     required_attrs: tuple[str, ...] = ("cursor", "status", "current-line")
     max_key_events: int | None = None
     expect_files: tuple[tuple[str, str], ...] = ()
+    prelude: str = ""
 
 
 def visible_controls(data: bytes) -> str:
@@ -456,10 +457,23 @@ def setup_multifile(tmp: Path) -> tuple[Path, str | None]:
     return beta, "beta\n"
 
 
+def setup_lsp_assist(tmp: Path) -> tuple[Path, str | None]:
+    target = tmp / "lsp.zig"
+    target.write_text("abc\n", encoding="utf-8")
+    return target, "abc\n"
+
+
 MOBILE_SYMBOL_SAVE_QUIT = tuple(bytes([b]) for b in b" ps w q")
 MOBILE_REPLACE_SAVE_QUIT = tuple(bytes([b]) for b in b"rx w q")
 ATTACHED_SAVE_QUIT = (b"i", b"\x1b[F", b"!", b"\x1b", b" ", b"w", b" ", b"q")
 PANEL_QUIT = (b" ", b"q")
+LSP_ASSIST_PRELUDE = "\n".join((
+    "lsp_hover_fixture zls|add(lhs, rhs)|Very long documentation that should stay viewport safe.",
+    "lsp_signature_fixture zls|add(lhs: i32, rhs: i32) active=rhs",
+    "diagnostic_fixture zls|1|lsp.zig|0|3|warning|demo",
+    "language_default_format zls",
+    "language_edit zls|format|1|0|3|ZLS",
+))
 
 IOS_DEFAULT_KEYS = set(b"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ ")
 
@@ -478,6 +492,7 @@ SCENARIOS = [
     Scenario("percent-match-jump", 56, 12, "brackets", "attached-keyboard", "match-jump", "truecolor", "file", setup_brackets, (b"%", b"i", b"X", b"\x1b", b" ", b"w", b" ", b"q"), "(abX)", ("1│", "☻")),
     Scenario("select-mode-colors", 56, 12, "short", "attached-keyboard", "select", "truecolor", "file", setup_short, (b"s", b"w", b"n", b" ", b"q"), "abcdef\n", ("attr:selection", "░", "mode:normal")),
     Scenario("multi-file-coding-loop", 72, 16, "repo-multifile", "attached-keyboard", "multi-file", "truecolor", "file", setup_multifile, (b"A", b"?", b"\x1b", b" ", b"w", b" ", b"o", b"r", b"e", b"p", b"o", b"/", b"a", b"l", b"p", b"h", b"a", b".", b"z", b"i", b"g", b"\r", b"A", b"!", b"\x1b", b" ", b"w", b" ", b"q"), None, ("alpha.zig", "beta", "☻", "mode:normal"), max_key_events=30, expect_files=(("alpha.zig", "alpha!\n"), ("beta.zig", "beta?"))),
+    Scenario("lsp-assisted-coding", 60, 12, "lsp-fixture", "attached-keyboard", "lsp", "truecolor", "file", setup_lsp_assist, (b" ", b"l", b"h", b" ", b"l", b"s", b" ", b"d", b"q", b" ", b"d", b"n", b" ", b"l", b"f", b" ", b"Q"), "abc\n", ("[zls] add(lhs, rhs)", "[zls] add(lhs: i32, rhs: i32) active=rhs", "diag:fresh:zls", "format:zls:applied", "ZLS", "mode:normal"), max_key_events=17, prelude=LSP_ASSIST_PRELUDE),
     Scenario("dirty-discard-shift-q", 52, 12, "empty", "ios-default-qwertz-space-path", "dirty-discard", "truecolor", "file", setup_empty, tuple(bytes([b]) for b in b" ps Q"), "", ("1│", "☻")),
     Scenario("directory-panel-narrow", 52, 12, "directory", "ios-default-qwertz-space-path", "panel", "mono", "directory", setup_directory, PANEL_QUIT, None, ("file", "one.zig"), required_attrs=()),
 ]
@@ -503,7 +518,12 @@ def run_one(mim: Path, root_out: Path, scenario: Scenario) -> tuple[str, Path]:
         target, expected_initial = scenario.setup(tmp)
         _ = expected_initial
         launch_arg = target.relative_to(tmp).as_posix()
-        pid, fd = spawn_under_pty([str(mim), launch_arg], scenario.width, scenario.height, scenario.color_mode, tmp)
+        argv = [str(mim), launch_arg]
+        if scenario.prelude:
+            prelude_path = tmp / "e2e-prelude.trace"
+            prelude_path.write_text(scenario.prelude + "\n", encoding="utf-8")
+            argv = [str(mim), "--e2e-prelude-file", prelude_path.name, launch_arg]
+        pid, fd = spawn_under_pty(argv, scenario.width, scenario.height, scenario.color_mode, tmp)
         transcript = bytearray()
         grid = TerminalGrid(scenario.width, scenario.height)
         try: