add contract hazard declaration, DO collection dates, and booking request currency migrations; implement article body diff component and integrate into contract revision timeline

apps/edr-freight-web/backoffice/src/components/contracts/ArticleBodyDiff.test.ts

@@ -0,0 +1,61 @@
+import { describe, expect, it } from "vitest";
+
+import { diffWords } from "./ArticleBodyDiff";
+
+/** Rebuild each side from the token stream — the diff must lose nothing. */
+const rebuild = (
+  tokens: ReturnType<typeof diffWords>,
+  side: "before" | "after",
+): string =>
+  tokens
+    .filter((t) =>
+      side === "before" ? t.op !== "added" : t.op !== "removed",
+    )
+    .map((t) => t.text)
+    .join("");
+
+describe("diffWords", () => {
+  it("marks only the words that actually changed", () => {
+    const tokens = diffWords(
+      "The carrier shall deliver within 30 days.",
+      "The carrier shall deliver within 45 days.",
+    );
+
+    expect(tokens.filter((t) => t.op === "removed").map((t) => t.text)).toEqual([
+      "30",
+    ]);
+    expect(tokens.filter((t) => t.op === "added").map((t) => t.text)).toEqual([
+      "45",
+    ]);
+  });
+
+  it("reconstructs both sides losslessly, whitespace included", () => {
+    const before = "Payment is due\nwithin ten (10) working days.";
+    const after = "Payment is due\nwithin five (5) working days of invoice.";
+    const tokens = diffWords(before, after);
+
+    expect(rebuild(tokens, "before")).toBe(before);
+    expect(rebuild(tokens, "after")).toBe(after);
+  });
+
+  it("reports nothing changed for identical text", () => {
+    const tokens = diffWords("Same clause.", "Same clause.");
+    expect(tokens.every((t) => t.op === "same")).toBe(true);
+  });
+
+  it("handles a body being emptied or written from scratch", () => {
+    expect(rebuild(diffWords("Some clause.", ""), "after")).toBe("");
+    expect(rebuild(diffWords("", "Brand new clause."), "before")).toBe("");
+  });
+
+  it("falls back to a whole-block replace on pathological input", () => {
+    // Past MAX_TOKENS the LCS table is skipped; the change must still be
+    // reported truthfully rather than silently dropped.
+    const before = Array.from({ length: 2000 }, (_, i) => `a${i}`).join(" ");
+    const after = Array.from({ length: 2000 }, (_, i) => `b${i}`).join(" ");
+    const tokens = diffWords(before, after);
+
+    expect(rebuild(tokens, "before")).toBe(before);
+    expect(rebuild(tokens, "after")).toBe(after);
+  });
+});