Fix bugs, improve schema gen

src/lib/schema/order-db-schema.test.ts

@@ -0,0 +1,73 @@
+import { describe, expect, test } from "bun:test";
+import type { BUN_MARIADB_TableSchemaType } from "../../types";
+import orderDBSchema from "./order-db-schema";
+
+function table({
+    name,
+    refs = [],
+}: {
+    name: string;
+    refs?: string[];
+}): BUN_MARIADB_TableSchemaType {
+    return {
+        tableName: name,
+        fields: refs.map((ref) => ({
+            fieldName: `${ref}_id`,
+            dataType: "BIGINT",
+            foreignKey: {
+                destinationTableName: ref,
+                destinationTableColumnName: "id",
+            },
+        })),
+    };
+}
+
+async function order(tables: BUN_MARIADB_TableSchemaType[]) {
+    const res = await orderDBSchema({ db_schema: { tables } });
+    return res.tables.map((t) => t.tableName);
+}
+
+describe("orderDBSchema", () => {
+    test("places parents before children", async () => {
+        expect(
+            await order([
+                table({ name: "comments", refs: ["posts", "users"] }),
+                table({ name: "posts", refs: ["users"] }),
+                table({ name: "users" }),
+            ]),
+        ).toEqual(["users", "posts", "comments"]);
+    });
+
+    test("keeps declaration order when there are no dependencies", async () => {
+        expect(
+            await order([table({ name: "b" }), table({ name: "a" })]),
+        ).toEqual(["b", "a"]);
+    });
+
+    test("handles self references without recursing forever", async () => {
+        expect(
+            await order([
+                table({ name: "categories", refs: ["categories"] }),
+                table({ name: "comments", refs: ["comments", "users"] }),
+                table({ name: "users" }),
+            ]),
+        ).toEqual(["categories", "users", "comments"]);
+    });
+
+    test("handles cycles and emits each table once", async () => {
+        const res = await order([
+            table({ name: "a", refs: ["b"] }),
+            table({ name: "b", refs: ["a"] }),
+            table({ name: "c", refs: ["a"] }),
+        ]);
+        expect(res).toHaveLength(3);
+        expect(new Set(res).size).toBe(3);
+        expect(res.indexOf("c")).toBeGreaterThan(res.indexOf("a"));
+    });
+
+    test("ignores references to tables outside the schema", async () => {
+        expect(
+            await order([table({ name: "posts", refs: ["external_users"] })]),
+        ).toEqual(["posts"]);
+    });
+});