[Init] Initial commit - NetMesh terminal manager

components/terminal/alignTerminalViewportScroll.test.ts

@@ -0,0 +1,100 @@
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import type { Terminal as XTerm } from "@xterm/xterm";
+import { alignTerminalViewportScroll } from "./terminalHelpers";
+
+type ViewportSpy = {
+  scrollToLine: (line: number, disableSmoothScroll?: boolean) => void;
+  _sync?: () => void;
+  calls: Array<{ line: number; disableSmoothScroll?: boolean }>;
+};
+
+const createTerm = (
+  viewportY: number,
+  viewport?: ViewportSpy | null,
+): XTerm => ({
+  buffer: { active: { viewportY } },
+  _core: viewport === null ? undefined : { _viewport: viewport },
+}) as unknown as XTerm;
+
+test("alignTerminalViewportScroll snaps the viewport back to the buffer row without smooth scrolling", () => {
+  const calls: Array<{ line: number; disableSmoothScroll?: boolean }> = [];
+  const viewport: ViewportSpy = {
+    scrollToLine: (line, disableSmoothScroll) => {
+      calls.push({ line, disableSmoothScroll });
+    },
+    calls,
+  };
+  const term = createTerm(247, viewport);
+
+  alignTerminalViewportScroll(term);
+
+  assert.deepEqual(calls, [{ line: 247, disableSmoothScroll: true }]);
+});
+
+test("alignTerminalViewportScroll syncs viewport dimensions before setting the position", () => {
+  const calls: Array<{ line: number; disableSmoothScroll?: boolean }> = [];
+  const order: string[] = [];
+  const viewport: ViewportSpy = {
+    _sync: () => {
+      order.push("sync");
+    },
+    scrollToLine: (line, disableSmoothScroll) => {
+      order.push("scrollToLine");
+      calls.push({ line, disableSmoothScroll });
+    },
+    calls,
+  };
+  const term = createTerm(247, viewport);
+
+  alignTerminalViewportScroll(term);
+
+  assert.deepEqual(order, ["sync", "scrollToLine"]);
+  assert.deepEqual(calls, [{ line: 247, disableSmoothScroll: true }]);
+});
+
+test("alignTerminalViewportScroll survives a failing dimension sync", () => {
+  const calls: Array<{ line: number; disableSmoothScroll?: boolean }> = [];
+  const viewport: ViewportSpy = {
+    _sync: () => {
+      throw new Error("boom");
+    },
+    scrollToLine: (line, disableSmoothScroll) => {
+      calls.push({ line, disableSmoothScroll });
+    },
+    calls,
+  };
+
+  assert.doesNotThrow(() => alignTerminalViewportScroll(createTerm(5, viewport)));
+  assert.deepEqual(calls, [{ line: 5, disableSmoothScroll: true }]);
+});
+
+test("alignTerminalViewportScroll is a no-op when the private viewport is unavailable", () => {
+  const term = createTerm(10, null);
+
+  assert.doesNotThrow(() => alignTerminalViewportScroll(term));
+});
+
+test("alignTerminalViewportScroll survives a viewport without scrollToLine", () => {
+  const term = {
+    buffer: { active: { viewportY: 5 } },
+    _core: { _viewport: {} },
+  } as unknown as XTerm;
+
+  assert.doesNotThrow(() => alignTerminalViewportScroll(term));
+});
+
+test("alignTerminalViewportScroll swallows viewport errors instead of breaking the fit", () => {
+  const term = {
+    buffer: { active: { viewportY: 5 } },
+    _core: {
+      _viewport: {
+        scrollToLine: () => {
+          throw new Error("boom");
+        },
+      },
+    },
+  } as unknown as XTerm;
+
+  assert.doesNotThrow(() => alignTerminalViewportScroll(term));
+});