hx: attempt to add tests in separate file

test/tests.zig

@@ -1,6 +1,7 @@
 const std = @import("std");
 pub const buffer = @import("tests_buffer.zig");
 pub const color = @import("tests_color.zig");
+pub const helix = @import("tests_helix.zig");
 
 test {
     std.testing.refAllDecls(@This());

test/tests_helix.zig

@@ -0,0 +1,79 @@
+const std = @import("std");
+const Buffer = @import("Buffer");
+const Cursor = @import("Cursor");
+const helix = @import("helix");
+
+// error: import of file outside module path
+// const helix = @import("../src/tui/mode/helix.zig");
+
+const ArrayList = std.ArrayList;
+const a = std.testing.allocator;
+
+fn metrics() Buffer.Metrics {
+    return .{
+        .ctx = undefined,
+        .egc_length = struct {
+            fn f(_: Buffer.Metrics, _: []const u8, colcount: *c_int, _: usize) usize {
+                colcount.* = 1;
+                return 1;
+            }
+        }.f,
+        .egc_chunk_width = struct {
+            fn f(_: Buffer.Metrics, chunk_: []const u8, _: usize) usize {
+                return chunk_.len;
+            }
+        }.f,
+        .egc_last = struct {
+            fn f(_: Buffer.Metrics, _: []const u8) []const u8 {
+                @panic("not implemented");
+            }
+        }.f,
+        .tab_width = 8,
+    };
+}
+
+fn the_pos(buffer: Buffer, pos: u8) Cursor {
+    return buffer.root.byte_offset_to_line_and_col(pos, metrics(), .lf);
+}
+
+test "word_movement" {
+    const W = helix.move_cursor_long_word_right;
+    const B = helix.move_cursor_long_word_left;
+    const E = helix.move_cursor_long_word_right_end;
+    const doc: []const u8 =
+        \\a small $% Test.here,   with.things()to demo
+        \\ with surrounding.space    a bb  AA   a small and long
+        \\
+        \\  
+        \\nospace.
+        \\   try std.testing.expectEqual(Buffer.Cursor{ .row = 0, .col = 0 }, buffer.root.byte_offset_to_line_and_col(0, test_metrics(), eol_mode));
+        \\
+        \\
+        \\  $$%.  []{{}. dart de
+        \\da
+    ;
+
+    //44 55 0 8 0
+    // TODO: test selections. Parity with Helix
+
+    var eol_mode: Buffer.EolMode = .lf;
+    var sanitized: bool = false;
+    const buffer = try Buffer.create(a);
+    defer buffer.deinit();
+    buffer.update(try buffer.load_from_string(doc, &eol_mode, &sanitized));
+    const root: Buffer.Root = buffer.root;
+    var c = Cursor{ .row = 0, .col = 0, .target = 0 };
+    const t = the_pos;
+
+    try std.testing.expectEqual(Buffer.Cursor{ .row = 0, .col = 0 }, buffer.root.byte_offset_to_line_and_col(0, metrics(), eol_mode));
+    try std.testing.expectEqual(try buffer.root.line_width(0, metrics()), 44);
+    try std.testing.expectEqual(try buffer.root.line_width(1, metrics()), 55);
+    try E(root, &c, metrics());
+    try std.testing.expectEqual(c, t(buffer.*, 1));
+    try B(root, &c, metrics());
+    try std.testing.expectEqual(c, t(buffer.*, 0));
+    try W(root, &c, metrics());
+    try std.testing.expectEqual(c, t(buffer.*, 2));
+    try B(root, &c, metrics());
+    try std.testing.expectEqual(c, t(buffer.*, 1));
+}