test: add edge case tests

src/dashboard/applyRawTaskContent.test.ts

@@ -68,4 +68,44 @@ body
 		if (result.isOk()) return;
 		expect(result.error.variant).toBe(AppErrorVariant.INVALID_TASK_FILE);
 	});
+
+	it("handles raw content with fields in different order", () => {
+		const raw = `---
+status: done
+id: "should-be-ignored"
+title: Reordered
+priority: low
+tags: [x, y]
+assignee: ""
+created: 2099-01-01T00:00:00.000Z
+updated: 2026-01-02T00:00:00.000Z
+---
+body text
+`;
+		const result = applyRawTaskContent(raw, previous);
+		expect(result.isOk()).toBe(true);
+		if (result.isErr()) return;
+		expect(result.value.title).toBe("Reordered");
+		expect(result.value.id).toBe(previous.id);
+		expect(result.value.created).toBe(previous.created);
+		expect(result.value.status).toBe(TaskStatus.DONE);
+	});
+
+	it("handles raw content with empty description body", () => {
+		const raw = `---
+id: "x"
+title: No body
+status: todo
+priority: medium
+tags: []
+assignee: ""
+created: 2026-01-01T00:00:00.000Z
+updated: 2026-01-01T00:00:00.000Z
+---
+`;
+		const result = applyRawTaskContent(raw, previous);
+		expect(result.isOk()).toBe(true);
+		if (result.isErr()) return;
+		expect(result.value.description).toBe("");
+	});
 });

src/dashboard/buildDashboardView.test.ts

@@ -80,4 +80,11 @@ describe("buildDashboardView", () => {
 		const view = buildDashboardView(tasks, { selectedId: "missing" });
 		expect(view.selected).toBeUndefined();
 	});
+
+	it("handles empty tasks array", () => {
+		const view = buildDashboardView([]);
+		expect(view.visibleTasks).toEqual([]);
+		expect(view.groups).toEqual([]);
+		expect(view.selected).toBeUndefined();
+	});
 });

src/dashboard/filterTasks.test.ts

@@ -98,4 +98,9 @@ describe("filterTasks", () => {
 		});
 		expect(result.map((t) => t.id)).toEqual(["4"]);
 	});
+
+	it("returns empty array for empty input", () => {
+		expect(filterTasks([], {})).toEqual([]);
+		expect(filterTasks([], { statuses: ["todo"] })).toEqual([]);
+	});
 });

src/dashboard/groupTasks.test.ts

@@ -93,4 +93,30 @@ describe("groupTasks", () => {
 		expect(groupTasks([], GroupBy.STATUS)).toEqual([]);
 		expect(groupTasks([], GroupBy.NONE)).toEqual([]);
 	});
+
+	it("silently drops tasks with unknown status from groups", () => {
+		const tasks: Task[] = [
+			task({ id: "a", title: "A", status: "__garbage__" as TaskStatus }),
+			task({ id: "b", title: "B", status: TaskStatus.TODO }),
+		];
+		const groups = groupTasks(tasks, GroupBy.STATUS);
+		const allGrouped = groups.flatMap((g) => g.tasks.map((t) => t.id));
+		expect(allGrouped).toEqual(["b"]);
+		expect(allGrouped).not.toContain("a");
+	});
+
+	it("silently drops tasks with unknown priority from groups", () => {
+		const tasks: Task[] = [
+			task({
+				id: "a",
+				title: "A",
+				priority: "__garbage__" as TaskPriority,
+			}),
+			task({ id: "b", title: "B", priority: TaskPriority.LOW }),
+		];
+		const groups = groupTasks(tasks, GroupBy.PRIORITY);
+		const allGrouped = groups.flatMap((g) => g.tasks.map((t) => t.id));
+		expect(allGrouped).toEqual(["b"]);
+		expect(allGrouped).not.toContain("a");
+	});
 });

src/dashboard/sortTasks.test.ts

@@ -61,4 +61,28 @@ describe("sortTasks", () => {
 		sortTasks(tasks, TaskSortDirection.DESC);
 		expect(tasks.map((t) => t.id)).toEqual(copy.map((t) => t.id));
 	});
+
+	it("returns empty array for empty input", () => {
+		expect(sortTasks([])).toEqual([]);
+	});
+
+	it("preserves input order when created dates are identical (stable sort)", () => {
+		const sameDate = "2026-01-01T00:00:00.000Z";
+		const tasks: Task[] = [
+			task({ id: "a", title: "A", created: sameDate }),
+			task({ id: "b", title: "B", created: sameDate }),
+			task({ id: "c", title: "C", created: sameDate }),
+		];
+		const result = sortTasks(tasks, TaskSortDirection.ASC);
+		expect(result.map((t) => t.id)).toEqual(["a", "b", "c"]);
+	});
+
+	it("handles invalid date strings without crashing", () => {
+		const tasks: Task[] = [
+			task({ id: "a", title: "A", created: "invalid-date" }),
+			task({ id: "b", title: "B", created: "2026-01-01T00:00:00.000Z" }),
+		];
+		const result = sortTasks(tasks, TaskSortDirection.ASC);
+		expect(result).toHaveLength(2);
+	});
 });

src/kanban/buildKanbanBoard.test.ts

@@ -117,4 +117,31 @@ describe("buildKanbanBoard", () => {
 			expect(col.tasks).toEqual([]);
 		}
 	});
+
+	it("preserves input order for tasks with same updated timestamp (stable sort)", () => {
+		const sameUpdated = "2026-01-01T00:00:00.000Z";
+		const tasks: Task[] = [
+			task({
+				id: "a",
+				title: "A",
+				status: TaskStatus.TODO,
+				updated: sameUpdated,
+			}),
+			task({
+				id: "b",
+				title: "B",
+				status: TaskStatus.TODO,
+				updated: sameUpdated,
+			}),
+			task({
+				id: "c",
+				title: "C",
+				status: TaskStatus.TODO,
+				updated: sameUpdated,
+			}),
+		];
+		const board = buildKanbanBoard(tasks);
+		const todo = board.columns.find((col) => col.status === TaskStatus.TODO);
+		expect(todo?.tasks.map((t) => t.id)).toEqual(["a", "b", "c"]);
+	});
 });

src/storage/FsTaskRepository.test.ts

@@ -195,4 +195,52 @@ describe("FsTaskRepository", () => {
 		expect(tasks[0].id).not.toBe(first.id);
 		expect(tasks[0].description).toBe("second");
 	});
+
+	it("creates task with Cyrillic title and slug", async () => {
+		const task = await repo.create(folder, {
+			...sampleTask,
+			title: "Тестовая задача",
+		});
+		expect(task.title).toBe("Тестовая задача");
+
+		const files = await fs.readdir(folder);
+		expect(files).toEqual([`тестовая-задача${TASK_FILE_EXTENSION}`]);
+	});
+
+	it("creates task with title exactly at MAX_TASK_TITLE_LENGTH", async () => {
+		const title = "a".repeat(80);
+		const task = await repo.create(folder, { ...sampleTask, title });
+		expect(task.title).toBe(title);
+
+		const files = await fs.readdir(folder);
+		expect(files).toEqual([`${title}${TASK_FILE_EXTENSION}`]);
+
+		const found = await repo.getById(folder, task.id);
+		expect(found?.title).toBe(title);
+	});
+
+	it("creates task with tags containing special characters", async () => {
+		const task = await repo.create(folder, {
+			...sampleTask,
+			tags: ["c#", "c++", "tag name", "tag:value"],
+		});
+
+		const files = await fs.readdir(folder);
+		expect(files).toHaveLength(1);
+
+		const content = await fs.readFile(
+			`${folder}/fix-login-bug${TASK_FILE_EXTENSION}`,
+		);
+		expect(content).toContain("c#");
+		expect(content).toContain("tag:value");
+	});
+
+	it("getFilePath produces consistent slug regardless of special characters", async () => {
+		const task = await repo.create(folder, {
+			...sampleTask,
+			title: "Fix___bug...",
+		});
+		const files = await fs.readdir(folder);
+		expect(files).toEqual([`fix-bug${TASK_FILE_EXTENSION}`]);
+	});
 });