Refactor Study Desk application structure

src/lib/progressNormalization.test.ts

@@ -0,0 +1,70 @@
+import { describe, expect, it } from "vitest";
+import { normalizeProgress } from "./progressNormalization";
+
+const isGrade = (value: unknown): value is "correct" | "missed" =>
+  value === "correct" || value === "missed";
+
+function normalize(order: string[], currentIndex: number, liveIds: string[]) {
+  return normalizeProgress({
+    orderJson: JSON.stringify(order),
+    currentIndex,
+    dataJson: JSON.stringify({ a: "correct", deleted: "missed" }),
+    liveIds,
+    isValidValue: isGrade,
+  });
+}
+
+describe("normalizeProgress", () => {
+  it("preserves the logical current card when a prior card was deleted", () => {
+    expect(normalize(["a", "b", "c"], 1, ["b", "c"]).currentIndex).toBe(0);
+  });
+
+  it("uses the next survivor when the current card was deleted", () => {
+    expect(normalize(["a", "b", "c"], 1, ["a", "c"]).currentIndex).toBe(1);
+  });
+
+  it("uses the previous survivor when no later card remains", () => {
+    expect(normalize(["a", "b", "c"], 2, ["a", "b"]).currentIndex).toBe(1);
+  });
+
+  it("preserves completed state after stale IDs are removed", () => {
+    const result = normalize(["a", "b", "c"], 3, ["a", "c"]);
+    expect(result.currentIndex).toBe(2);
+    expect(result.completed).toBe(true);
+  });
+
+  it("recovers malformed JSON and filters stale result keys", () => {
+    const result = normalizeProgress({
+      orderJson: "not-json",
+      currentIndex: -1,
+      dataJson: '{"a":"correct","b":"invalid"}',
+      liveIds: ["a", "b"],
+      isValidValue: isGrade,
+    });
+    expect(result).toMatchObject({
+      order: ["a", "b"],
+      currentIndex: 0,
+      data: { a: "correct" },
+      completed: false,
+      wasRecovered: true,
+    });
+  });
+
+  it("returns a clear completed state when all saved cards were deleted", () => {
+    const result = normalize(["deleted"], 0, []);
+    expect(result).toMatchObject({ order: [], currentIndex: 0, completed: true });
+  });
+
+  it("lets content-specific validation reject a value owned by another item", () => {
+    const result = normalizeProgress({
+      orderJson: '["q1","q2"]',
+      currentIndex: 0,
+      dataJson: '{"q1":["q2-option"]}',
+      liveIds: ["q1", "q2"],
+      isValidValue: (value, id): value is string[] =>
+        Array.isArray(value) && value.every((optionId) => optionId === `${id}-option`),
+    });
+    expect(result.data).toEqual({});
+    expect(result.wasRecovered).toBe(true);
+  });
+});