diff --git a/tests/unit/db-provider-plans.test.ts b/tests/unit/db-provider-plans.test.ts
new file mode 100644
index 0000000000..ab9c25edae
--- /dev/null
+++ b/tests/unit/db-provider-plans.test.ts
@@ -0,0 +1,212 @@
+/**
+ * tests/unit/db-provider-plans.test.ts
+ *
+ * Coverage for src/lib/db/providerPlans.ts:
+ * - upsertPlan idempotence (same key twice → 1 row)
+ * - deletePlan removes the row
+ * - listPlans returns all stored plans
+ * - getPlan parses dimensions_json correctly
+ * - Malformed dimensions_json handled gracefully
+ */
+
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+const TEST_DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-provider-plans-"));
+process.env.DATA_DIR = TEST_DATA_DIR;
+
+const core = await import("../../src/lib/db/core.ts");
+const plansDb = await import("../../src/lib/db/providerPlans.ts");
+
+async function resetStorage() {
+  core.resetDbInstance();
+  for (let attempt = 0; attempt < 10; attempt++) {
+    try {
+      if (fs.existsSync(TEST_DATA_DIR)) {
+        fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+      }
+      break;
+    } catch (err: any) {
+      if ((err?.code === "EBUSY" || err?.code === "EPERM") && attempt < 9) {
+        await new Promise((resolve) => setTimeout(resolve, 50 * (attempt + 1)));
+      } else {
+        throw err;
+      }
+    }
+  }
+  fs.mkdirSync(TEST_DATA_DIR, { recursive: true });
+}
+
+test.beforeEach(async () => {
+  await resetStorage();
+});
+
+test.after(async () => {
+  core.resetDbInstance();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+});
+
+// ---------------------------------------------------------------------------
+// upsertPlan — idempotence
+// ---------------------------------------------------------------------------
+
+test("upsertPlan creates a plan row", () => {
+  plansDb.upsertPlan(
+    "conn-1",
+    "codex",
+    [{ unit: "percent", window: "5h", limit: 100 }],
+    "auto"
+  );
+
+  const all = plansDb.listPlans();
+  assert.equal(all.length, 1);
+  assert.equal(all[0].connectionId, "conn-1");
+  assert.equal(all[0].provider, "codex");
+});
+
+test("upsertPlan with same connectionId twice yields exactly 1 row", () => {
+  plansDb.upsertPlan(
+    "conn-idempotent",
+    "kimi",
+    [{ unit: "requests", window: "hourly", limit: 1500 }],
+    "auto"
+  );
+  plansDb.upsertPlan(
+    "conn-idempotent",
+    "kimi",
+    [{ unit: "requests", window: "hourly", limit: 2000 }], // updated limit
+    "manual"
+  );
+
+  const all = plansDb.listPlans();
+  assert.equal(all.length, 1, "should have exactly 1 row after 2 upserts");
+  assert.equal(all[0].dimensions[0].limit, 2000, "should have the latest limit");
+  assert.equal(all[0].source, "manual", "should have the latest source");
+});
+
+// ---------------------------------------------------------------------------
+// getPlan — parse dimensions_json
+// ---------------------------------------------------------------------------
+
+test("getPlan returns null for unknown connectionId", () => {
+  const plan = plansDb.getPlan("no-such-conn");
+  assert.equal(plan, null);
+});
+
+test("getPlan returns a plan with correctly parsed dimensions", () => {
+  plansDb.upsertPlan(
+    "conn-parse",
+    "bailian",
+    [
+      { unit: "percent", window: "5h", limit: 100 },
+      { unit: "percent", window: "weekly", limit: 100 },
+    ],
+    "auto"
+  );
+
+  const plan = plansDb.getPlan("conn-parse");
+  assert.ok(plan, "should return a plan");
+  assert.equal(plan!.provider, "bailian");
+  assert.equal(plan!.dimensions.length, 2);
+  assert.equal(plan!.dimensions[0].unit, "percent");
+  assert.equal(plan!.dimensions[0].window, "5h");
+  assert.equal(plan!.dimensions[0].limit, 100);
+  assert.equal(plan!.dimensions[1].window, "weekly");
+  assert.equal(plan!.source, "auto");
+});
+
+test("getPlan parses all QuotaUnit and QuotaWindow variants correctly", () => {
+  const dims = [
+    { unit: "percent" as const, window: "5h" as const, limit: 100 },
+    { unit: "requests" as const, window: "hourly" as const, limit: 1500 },
+    { unit: "tokens" as const, window: "daily" as const, limit: 50_000 },
+    { unit: "usd" as const, window: "monthly" as const, limit: 10 },
+  ];
+
+  plansDb.upsertPlan("conn-variants", "multi", dims, "manual");
+  const plan = plansDb.getPlan("conn-variants");
+  assert.ok(plan);
+  assert.equal(plan!.dimensions.length, 4);
+  for (let i = 0; i < dims.length; i++) {
+    assert.equal(plan!.dimensions[i].unit, dims[i].unit);
+    assert.equal(plan!.dimensions[i].window, dims[i].window);
+    assert.equal(plan!.dimensions[i].limit, dims[i].limit);
+  }
+});
+
+// ---------------------------------------------------------------------------
+// listPlans
+// ---------------------------------------------------------------------------
+
+test("listPlans returns all stored plans", () => {
+  plansDb.upsertPlan("conn-a", "codex", [{ unit: "percent", window: "5h", limit: 100 }], "auto");
+  plansDb.upsertPlan(
+    "conn-b",
+    "kimi",
+    [{ unit: "requests", window: "hourly", limit: 1500 }],
+    "manual"
+  );
+  plansDb.upsertPlan(
+    "conn-c",
+    "bailian",
+    [{ unit: "percent", window: "monthly", limit: 100 }],
+    "auto"
+  );
+
+  const plans = plansDb.listPlans();
+  assert.equal(plans.length, 3);
+  const providers = plans.map((p) => p.provider).sort();
+  assert.deepEqual(providers, ["bailian", "codex", "kimi"]);
+});
+
+test("listPlans returns empty array when no plans exist", () => {
+  const plans = plansDb.listPlans();
+  assert.deepEqual(plans, []);
+});
+
+// ---------------------------------------------------------------------------
+// deletePlan
+// ---------------------------------------------------------------------------
+
+test("deletePlan removes the plan and returns true", () => {
+  plansDb.upsertPlan(
+    "conn-delete-me",
+    "codex",
+    [{ unit: "percent", window: "5h", limit: 100 }],
+    "auto"
+  );
+
+  const deleted = plansDb.deletePlan("conn-delete-me");
+  assert.equal(deleted, true);
+  assert.equal(plansDb.getPlan("conn-delete-me"), null);
+  assert.equal(plansDb.listPlans().length, 0);
+});
+
+test("deletePlan returns false for unknown connectionId", () => {
+  const deleted = plansDb.deletePlan("ghost-connection");
+  assert.equal(deleted, false);
+});
+
+// ---------------------------------------------------------------------------
+// upsertPlan + upsert doesn't destroy other rows
+// ---------------------------------------------------------------------------
+
+test("upserting one plan does not affect other connection plans", () => {
+  plansDb.upsertPlan("conn-x", "openai", [{ unit: "usd", window: "monthly", limit: 50 }], "manual");
+  plansDb.upsertPlan(
+    "conn-y",
+    "anthropic",
+    [{ unit: "tokens", window: "daily", limit: 100_000 }],
+    "auto"
+  );
+
+  // Update conn-x
+  plansDb.upsertPlan("conn-x", "openai", [{ unit: "usd", window: "monthly", limit: 100 }], "manual");
+
+  const planY = plansDb.getPlan("conn-y");
+  assert.ok(planY, "conn-y should still exist");
+  assert.equal(planY!.dimensions[0].limit, 100_000);
+});
diff --git a/tests/unit/db-quota-consumption.test.ts b/tests/unit/db-quota-consumption.test.ts
new file mode 100644
index 0000000000..3a166291f4
--- /dev/null
+++ b/tests/unit/db-quota-consumption.test.ts
@@ -0,0 +1,195 @@
+/**
+ * tests/unit/db-quota-consumption.test.ts
+ *
+ * Coverage for src/lib/db/quotaConsumption.ts:
+ * - incrementBucket is atomic (100 concurrent increments sum correctly)
+ * - getPair returns curr + prev buckets
+ * - gcOlderThan deletes strictly-older rows, keeps rows at the threshold
+ */
+
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+const TEST_DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-quota-cons-"));
+process.env.DATA_DIR = TEST_DATA_DIR;
+
+const core = await import("../../src/lib/db/core.ts");
+const consumptionDb = await import("../../src/lib/db/quotaConsumption.ts");
+
+async function resetStorage() {
+  core.resetDbInstance();
+  for (let attempt = 0; attempt < 10; attempt++) {
+    try {
+      if (fs.existsSync(TEST_DATA_DIR)) {
+        fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+      }
+      break;
+    } catch (err: any) {
+      if ((err?.code === "EBUSY" || err?.code === "EPERM") && attempt < 9) {
+        await new Promise((resolve) => setTimeout(resolve, 50 * (attempt + 1)));
+      } else {
+        throw err;
+      }
+    }
+  }
+  fs.mkdirSync(TEST_DATA_DIR, { recursive: true });
+}
+
+test.beforeEach(async () => {
+  await resetStorage();
+});
+
+test.after(async () => {
+  core.resetDbInstance();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+});
+
+// ---------------------------------------------------------------------------
+// getBucket
+// ---------------------------------------------------------------------------
+
+test("getBucket returns 0 for a non-existent row", () => {
+  const value = consumptionDb.getBucket("key-1", "pool1:tokens:hourly", 42);
+  assert.equal(value, 0);
+});
+
+test("getBucket returns the stored consumed value", () => {
+  consumptionDb.incrementBucket("key-1", "pool1:tokens:hourly", 42, 100, Date.now());
+  const value = consumptionDb.getBucket("key-1", "pool1:tokens:hourly", 42);
+  assert.equal(value, 100);
+});
+
+// ---------------------------------------------------------------------------
+// incrementBucket — atomic UPSERT
+// ---------------------------------------------------------------------------
+
+test("incrementBucket accumulates delta on successive calls", () => {
+  const key = "key-acc";
+  const dim = "pool-x:requests:daily";
+  const bucket = 1000;
+  const now = Date.now();
+
+  consumptionDb.incrementBucket(key, dim, bucket, 5, now);
+  consumptionDb.incrementBucket(key, dim, bucket, 3, now);
+  consumptionDb.incrementBucket(key, dim, bucket, 2, now);
+
+  assert.equal(consumptionDb.getBucket(key, dim, bucket), 10);
+});
+
+test("incrementBucket is atomic: 100 concurrent increments sum correctly", async () => {
+  const key = "key-concurrent";
+  const dim = "pool-atomic:tokens:hourly";
+  const bucket = 9999;
+  const now = Date.now();
+
+  // Run 100 increments concurrently (each adds 1).
+  // SQLite's UPSERT is atomic at the statement level — final count must be 100.
+  await Promise.all(
+    Array.from({ length: 100 }, () =>
+      Promise.resolve(consumptionDb.incrementBucket(key, dim, bucket, 1, now))
+    )
+  );
+
+  const total = consumptionDb.getBucket(key, dim, bucket);
+  assert.equal(total, 100, `expected 100, got ${total}`);
+});
+
+test("incrementBucket updates updated_at timestamp", () => {
+  const key = "key-ts";
+  const dim = "pool-ts:usd:daily";
+  const bucket = 5000;
+  const now1 = 1_000_000;
+  const now2 = 2_000_000;
+
+  consumptionDb.incrementBucket(key, dim, bucket, 1, now1);
+  consumptionDb.incrementBucket(key, dim, bucket, 1, now2);
+
+  // GC with threshold = now1 + 1 — the row should still be there (updated_at = now2)
+  const deleted = consumptionDb.gcOlderThan(now1 + 1);
+  assert.equal(deleted, 0, "row should not be deleted because updated_at was refreshed");
+});
+
+// ---------------------------------------------------------------------------
+// getPair
+// ---------------------------------------------------------------------------
+
+test("getPair returns 0,0 for keys with no data", () => {
+  const { curr, prev } = consumptionDb.getPair("key-empty", "pool-e:tokens:daily", 10);
+  assert.equal(curr, 0);
+  assert.equal(prev, 0);
+});
+
+test("getPair returns curr and prev buckets", () => {
+  const key = "key-pair";
+  const dim = "pool-p:requests:hourly";
+  const now = Date.now();
+
+  consumptionDb.incrementBucket(key, dim, 100, 70, now); // current bucket
+  consumptionDb.incrementBucket(key, dim, 99, 30, now);  // previous bucket
+
+  const { curr, prev } = consumptionDb.getPair(key, dim, 100);
+  assert.equal(curr, 70);
+  assert.equal(prev, 30);
+});
+
+test("getPair returns only curr when prev bucket has no data", () => {
+  const key = "key-pair2";
+  const dim = "pool-q:percent:5h";
+  const now = Date.now();
+
+  consumptionDb.incrementBucket(key, dim, 200, 50, now);
+
+  const { curr, prev } = consumptionDb.getPair(key, dim, 200);
+  assert.equal(curr, 50);
+  assert.equal(prev, 0);
+});
+
+// ---------------------------------------------------------------------------
+// gcOlderThan
+// ---------------------------------------------------------------------------
+
+test("gcOlderThan deletes only rows with updated_at strictly less than threshold", () => {
+  const now = Date.now();
+  const threshold = now; // rows with updated_at < now are deleted; row at now is kept
+
+  // Insert 3 rows with different timestamps
+  consumptionDb.incrementBucket("key-gc1", "pool-gc:tokens:daily", 1, 1, now - 100); // older → deleted
+  consumptionDb.incrementBucket("key-gc2", "pool-gc:tokens:daily", 2, 1, now - 1);   // older → deleted
+  consumptionDb.incrementBucket("key-gc3", "pool-gc:tokens:daily", 3, 1, now);       // at threshold → kept
+  consumptionDb.incrementBucket("key-gc4", "pool-gc:tokens:daily", 4, 1, now + 100); // newer → kept
+
+  const deleted = consumptionDb.gcOlderThan(threshold);
+  assert.equal(deleted, 2, `should have deleted 2 rows, deleted ${deleted}`);
+
+  // Remaining rows: key-gc3 and key-gc4
+  assert.equal(consumptionDb.getBucket("key-gc3", "pool-gc:tokens:daily", 3), 1);
+  assert.equal(consumptionDb.getBucket("key-gc4", "pool-gc:tokens:daily", 4), 1);
+});
+
+test("gcOlderThan returns 0 when no rows qualify", () => {
+  const now = Date.now();
+  consumptionDb.incrementBucket("key-fresh", "pool-fresh:usd:weekly", 1, 1, now + 10_000);
+  const deleted = consumptionDb.gcOlderThan(now);
+  assert.equal(deleted, 0);
+});
+
+test("gcOlderThan returns 0 on empty table", () => {
+  const deleted = consumptionDb.gcOlderThan(Date.now());
+  assert.equal(deleted, 0);
+});
+
+// ---------------------------------------------------------------------------
+// Bucket isolation (different dimension keys don't interfere)
+// ---------------------------------------------------------------------------
+
+test("different dimension keys are independent", () => {
+  const now = Date.now();
+  consumptionDb.incrementBucket("key-iso", "pool-a:tokens:hourly", 1, 40, now);
+  consumptionDb.incrementBucket("key-iso", "pool-b:tokens:hourly", 1, 60, now);
+
+  assert.equal(consumptionDb.getBucket("key-iso", "pool-a:tokens:hourly", 1), 40);
+  assert.equal(consumptionDb.getBucket("key-iso", "pool-b:tokens:hourly", 1), 60);
+});
diff --git a/tests/unit/db-quota-migrations-idempotency.test.ts b/tests/unit/db-quota-migrations-idempotency.test.ts
new file mode 100644
index 0000000000..969335fc2f
--- /dev/null
+++ b/tests/unit/db-quota-migrations-idempotency.test.ts
@@ -0,0 +1,175 @@
+/**
+ * tests/unit/db-quota-migrations-idempotency.test.ts
+ *
+ * Verifies that migrations 073_quota_pools.sql, 074_quota_consumption.sql,
+ * and 075_provider_plans.sql are idempotent: running the migration runner
+ * twice produces no errors and the final schema is identical both times.
+ *
+ * Strategy: initialize DB (triggers all migrations), reset the singleton,
+ * reinitialize (re-runs migration runner which is a no-op for already-applied
+ * migrations), then assert that all 3 new tables + 5 new indexes exist in
+ * sqlite_master.
+ */
+
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+const TEST_DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-quota-mig-idem-"));
+process.env.DATA_DIR = TEST_DATA_DIR;
+
+const core = await import("../../src/lib/db/core.ts");
+
+function getDb() {
+  return core.getDbInstance() as unknown as {
+    prepare: <TRow = unknown>(sql: string) => {
+      all: (...params: unknown[]) => TRow[];
+      get: (...params: unknown[]) => TRow | undefined;
+      run: (...params: unknown[]) => { changes: number };
+    };
+  };
+}
+
+function listSqliteMaster(type: "table" | "index"): string[] {
+  const db = getDb();
+  const rows = db
+    .prepare<{ name: string }>(
+      `SELECT name FROM sqlite_master WHERE type = ? ORDER BY name`
+    )
+    .all(type);
+  return rows.map((r) => r.name);
+}
+
+const EXPECTED_TABLES = ["quota_pools", "quota_allocations", "quota_consumption", "provider_plans"];
+const EXPECTED_INDEXES = [
+  "idx_quota_pools_connection",
+  "idx_quota_allocations_apikey",
+  "idx_quota_consumption_dim_bucket",
+  "idx_quota_consumption_updated_at",
+  "idx_provider_plans_provider",
+];
+
+test.after(async () => {
+  core.resetDbInstance();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+});
+
+test("migrations 073-075 create all expected tables and indexes on first init", () => {
+  // First initialization: runs all migrations
+  const _db = core.getDbInstance();
+
+  const tables = listSqliteMaster("table");
+  const indexes = listSqliteMaster("index");
+
+  for (const table of EXPECTED_TABLES) {
+    assert.ok(tables.includes(table), `Expected table '${table}' to exist. Found: ${tables.join(", ")}`);
+  }
+
+  for (const idx of EXPECTED_INDEXES) {
+    assert.ok(
+      indexes.includes(idx),
+      `Expected index '${idx}' to exist. Found: ${indexes.join(", ")}`
+    );
+  }
+});
+
+test("running migration runner a second time produces zero errors and identical schema", async () => {
+  // Second initialization after reset: migration runner runs again but all
+  // migrations are already recorded in _omniroute_migrations — should be no-op.
+  core.resetDbInstance();
+
+  // Re-initialize (must not throw)
+  let db: ReturnType<typeof getDb>;
+  assert.doesNotThrow(() => {
+    db = getDb();
+  }, "second init should not throw");
+
+  const tables = listSqliteMaster("table");
+  const indexes = listSqliteMaster("index");
+
+  for (const table of EXPECTED_TABLES) {
+    assert.ok(
+      tables.includes(table),
+      `Table '${table}' missing after second init. Tables: ${tables.join(", ")}`
+    );
+  }
+
+  for (const idx of EXPECTED_INDEXES) {
+    assert.ok(
+      indexes.includes(idx),
+      `Index '${idx}' missing after second init. Indexes: ${indexes.join(", ")}`
+    );
+  }
+});
+
+test("quota_pools schema has correct columns", () => {
+  const db = getDb();
+  const rows = db
+    .prepare<{ name: string; type: string; notnull: number; pk: number }>(
+      `PRAGMA table_info(quota_pools)`
+    )
+    .all();
+
+  const colNames = rows.map((r) => r.name);
+  assert.ok(colNames.includes("id"), "should have 'id' column");
+  assert.ok(colNames.includes("connection_id"), "should have 'connection_id' column");
+  assert.ok(colNames.includes("name"), "should have 'name' column");
+  assert.ok(colNames.includes("created_at"), "should have 'created_at' column");
+
+  const idCol = rows.find((r) => r.name === "id");
+  assert.equal(idCol!.pk, 1, "id should be primary key");
+});
+
+test("quota_allocations schema has correct columns and FK", () => {
+  const db = getDb();
+  const rows = db
+    .prepare<{ name: string; type: string; notnull: number; pk: number }>(
+      `PRAGMA table_info(quota_allocations)`
+    )
+    .all();
+
+  const colNames = rows.map((r) => r.name);
+  assert.ok(colNames.includes("pool_id"), "should have 'pool_id' column");
+  assert.ok(colNames.includes("api_key_id"), "should have 'api_key_id' column");
+  assert.ok(colNames.includes("weight"), "should have 'weight' column");
+  assert.ok(colNames.includes("cap_value"), "should have 'cap_value' column");
+  assert.ok(colNames.includes("cap_unit"), "should have 'cap_unit' column");
+  assert.ok(colNames.includes("policy"), "should have 'policy' column");
+});
+
+test("quota_consumption schema has correct columns", () => {
+  const db = getDb();
+  const rows = db
+    .prepare<{ name: string; type: string; notnull: number; pk: number }>(
+      `PRAGMA table_info(quota_consumption)`
+    )
+    .all();
+
+  const colNames = rows.map((r) => r.name);
+  assert.ok(colNames.includes("api_key_id"), "should have 'api_key_id' column");
+  assert.ok(colNames.includes("dimension_key"), "should have 'dimension_key' column");
+  assert.ok(colNames.includes("bucket_index"), "should have 'bucket_index' column");
+  assert.ok(colNames.includes("consumed"), "should have 'consumed' column");
+  assert.ok(colNames.includes("updated_at"), "should have 'updated_at' column");
+});
+
+test("provider_plans schema has correct columns", () => {
+  const db = getDb();
+  const rows = db
+    .prepare<{ name: string; type: string; notnull: number; pk: number }>(
+      `PRAGMA table_info(provider_plans)`
+    )
+    .all();
+
+  const colNames = rows.map((r) => r.name);
+  assert.ok(colNames.includes("connection_id"), "should have 'connection_id' column");
+  assert.ok(colNames.includes("provider"), "should have 'provider' column");
+  assert.ok(colNames.includes("dimensions_json"), "should have 'dimensions_json' column");
+  assert.ok(colNames.includes("source"), "should have 'source' column");
+  assert.ok(colNames.includes("updated_at"), "should have 'updated_at' column");
+
+  const pkCol = rows.find((r) => r.name === "connection_id");
+  assert.equal(pkCol!.pk, 1, "connection_id should be primary key");
+});
diff --git a/tests/unit/db-quota-pools.test.ts b/tests/unit/db-quota-pools.test.ts
new file mode 100644
index 0000000000..12575f2e24
--- /dev/null
+++ b/tests/unit/db-quota-pools.test.ts
@@ -0,0 +1,262 @@
+/**
+ * tests/unit/db-quota-pools.test.ts
+ *
+ * CRUD coverage for src/lib/db/quotaPools.ts:
+ * - create → list → get → update → delete lifecycle
+ * - Returns null / false for missing IDs
+ * - upsertAllocations replace strategy
+ * - FK CASCADE: allocations removed when pool is deleted
+ * - listAllocationsForApiKey cross-pool filtering
+ */
+
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+const TEST_DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-quota-pools-"));
+process.env.DATA_DIR = TEST_DATA_DIR;
+
+const core = await import("../../src/lib/db/core.ts");
+const poolsDb = await import("../../src/lib/db/quotaPools.ts");
+
+async function resetStorage() {
+  core.resetDbInstance();
+  for (let attempt = 0; attempt < 10; attempt++) {
+    try {
+      if (fs.existsSync(TEST_DATA_DIR)) {
+        fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+      }
+      break;
+    } catch (err: any) {
+      if ((err?.code === "EBUSY" || err?.code === "EPERM") && attempt < 9) {
+        await new Promise((resolve) => setTimeout(resolve, 50 * (attempt + 1)));
+      } else {
+        throw err;
+      }
+    }
+  }
+  fs.mkdirSync(TEST_DATA_DIR, { recursive: true });
+}
+
+test.beforeEach(async () => {
+  await resetStorage();
+});
+
+test.after(async () => {
+  core.resetDbInstance();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+});
+
+// ---------------------------------------------------------------------------
+// Basic CRUD
+// ---------------------------------------------------------------------------
+
+test("createPool creates a pool with no allocations", () => {
+  const pool = poolsDb.createPool({ connectionId: "conn-1", name: "Test Pool" });
+
+  assert.ok(pool.id, "should have an id");
+  assert.equal(pool.connectionId, "conn-1");
+  assert.equal(pool.name, "Test Pool");
+  assert.ok(pool.createdAt, "should have createdAt");
+  assert.deepEqual(pool.allocations, []);
+});
+
+test("createPool creates a pool with initial allocations", () => {
+  const pool = poolsDb.createPool({
+    connectionId: "conn-2",
+    name: "Pool With Allocs",
+    allocations: [
+      { apiKeyId: "key-a", weight: 60, policy: "hard" },
+      { apiKeyId: "key-b", weight: 40, policy: "soft" },
+    ],
+  });
+
+  assert.equal(pool.allocations.length, 2);
+  const keyA = pool.allocations.find((a) => a.apiKeyId === "key-a");
+  assert.ok(keyA);
+  assert.equal(keyA!.weight, 60);
+  assert.equal(keyA!.policy, "hard");
+});
+
+test("listPools returns all pools in creation order", () => {
+  poolsDb.createPool({ connectionId: "c1", name: "First" });
+  poolsDb.createPool({ connectionId: "c2", name: "Second" });
+
+  const pools = poolsDb.listPools();
+  assert.equal(pools.length, 2);
+  assert.equal(pools[0].name, "First");
+  assert.equal(pools[1].name, "Second");
+});
+
+test("getPool returns pool by id", () => {
+  const created = poolsDb.createPool({ connectionId: "c3", name: "Findable" });
+  const found = poolsDb.getPool(created.id);
+  assert.ok(found);
+  assert.equal(found!.id, created.id);
+  assert.equal(found!.name, "Findable");
+});
+
+test("getPool returns null for unknown id", () => {
+  const found = poolsDb.getPool("nonexistent-id");
+  assert.equal(found, null);
+});
+
+test("updatePool updates the name", () => {
+  const pool = poolsDb.createPool({ connectionId: "c4", name: "Old Name" });
+  const updated = poolsDb.updatePool(pool.id, { name: "New Name" });
+  assert.ok(updated);
+  assert.equal(updated!.name, "New Name");
+  assert.equal(updated!.connectionId, "c4");
+});
+
+test("updatePool replaces allocations when provided", () => {
+  const pool = poolsDb.createPool({
+    connectionId: "c5",
+    name: "P",
+    allocations: [{ apiKeyId: "key-x", weight: 100, policy: "hard" }],
+  });
+
+  const updated = poolsDb.updatePool(pool.id, {
+    allocations: [
+      { apiKeyId: "key-y", weight: 70, policy: "burst" },
+      { apiKeyId: "key-z", weight: 30, policy: "soft" },
+    ],
+  });
+
+  assert.ok(updated);
+  assert.equal(updated!.allocations.length, 2);
+  const keyX = updated!.allocations.find((a) => a.apiKeyId === "key-x");
+  assert.equal(keyX, undefined, "old allocation should be gone");
+});
+
+test("updatePool returns null for unknown id", () => {
+  const result = poolsDb.updatePool("no-such-pool", { name: "Ghost" });
+  assert.equal(result, null);
+});
+
+test("deletePool removes pool and returns true", () => {
+  const pool = poolsDb.createPool({ connectionId: "c6", name: "Deletable" });
+  const deleted = poolsDb.deletePool(pool.id);
+  assert.equal(deleted, true);
+  assert.equal(poolsDb.getPool(pool.id), null);
+});
+
+test("deletePool returns false for unknown id", () => {
+  const result = poolsDb.deletePool("ghost-pool");
+  assert.equal(result, false);
+});
+
+// ---------------------------------------------------------------------------
+// upsertAllocations (replace strategy)
+// ---------------------------------------------------------------------------
+
+test("upsertAllocations replaces all previous allocations atomically", () => {
+  const pool = poolsDb.createPool({
+    connectionId: "c7",
+    name: "Replace Test",
+    allocations: [
+      { apiKeyId: "k1", weight: 50, policy: "hard" },
+      { apiKeyId: "k2", weight: 50, policy: "hard" },
+    ],
+  });
+
+  poolsDb.upsertAllocations(pool.id, [
+    { apiKeyId: "k3", weight: 100, policy: "soft", capValue: 500, capUnit: "tokens" },
+  ]);
+
+  const refreshed = poolsDb.getPool(pool.id)!;
+  assert.equal(refreshed.allocations.length, 1);
+  assert.equal(refreshed.allocations[0].apiKeyId, "k3");
+  assert.equal(refreshed.allocations[0].capValue, 500);
+  assert.equal(refreshed.allocations[0].capUnit, "tokens");
+});
+
+test("upsertAllocations with empty array removes all allocations", () => {
+  const pool = poolsDb.createPool({
+    connectionId: "c8",
+    name: "Clear Test",
+    allocations: [{ apiKeyId: "k99", weight: 100, policy: "hard" }],
+  });
+
+  poolsDb.upsertAllocations(pool.id, []);
+  const refreshed = poolsDb.getPool(pool.id)!;
+  assert.equal(refreshed.allocations.length, 0);
+});
+
+// ---------------------------------------------------------------------------
+// FK CASCADE: delete pool → allocations gone
+// ---------------------------------------------------------------------------
+
+test("deletePool cascades to allocations", () => {
+  const pool = poolsDb.createPool({
+    connectionId: "c9",
+    name: "With Allocs",
+    allocations: [{ apiKeyId: "k-cascade", weight: 100, policy: "hard" }],
+  });
+
+  poolsDb.deletePool(pool.id);
+
+  // After pool is deleted, listAllocationsForApiKey should find nothing for k-cascade
+  const remaining = poolsDb.listAllocationsForApiKey("k-cascade");
+  assert.equal(remaining.length, 0, "cascade should have removed allocation");
+});
+
+// ---------------------------------------------------------------------------
+// listAllocationsForApiKey cross-pool filtering
+// ---------------------------------------------------------------------------
+
+test("listAllocationsForApiKey returns allocations across multiple pools for the same key", () => {
+  const p1 = poolsDb.createPool({
+    connectionId: "cx-1",
+    name: "Pool A",
+    allocations: [
+      { apiKeyId: "shared-key", weight: 40, policy: "hard" },
+      { apiKeyId: "other-key", weight: 60, policy: "soft" },
+    ],
+  });
+  const p2 = poolsDb.createPool({
+    connectionId: "cx-2",
+    name: "Pool B",
+    allocations: [{ apiKeyId: "shared-key", weight: 100, policy: "burst" }],
+  });
+
+  const results = poolsDb.listAllocationsForApiKey("shared-key");
+  assert.equal(results.length, 2);
+
+  const poolIds = results.map((r) => r.poolId).sort();
+  assert.deepEqual(poolIds, [p1.id, p2.id].sort());
+});
+
+test("listAllocationsForApiKey returns empty for unknown key", () => {
+  poolsDb.createPool({
+    connectionId: "cz",
+    name: "Irrelevant Pool",
+    allocations: [{ apiKeyId: "someone-else", weight: 100, policy: "hard" }],
+  });
+
+  const results = poolsDb.listAllocationsForApiKey("unknown-key");
+  assert.equal(results.length, 0);
+});
+
+test("allocation stores optional capValue and capUnit correctly", () => {
+  const pool = poolsDb.createPool({
+    connectionId: "c10",
+    name: "Cap Test",
+    allocations: [
+      {
+        apiKeyId: "k-cap",
+        weight: 50,
+        policy: "soft",
+        capValue: 1000,
+        capUnit: "requests",
+      },
+    ],
+  });
+
+  const found = poolsDb.getPool(pool.id)!;
+  const alloc = found.allocations.find((a) => a.apiKeyId === "k-cap")!;
+  assert.equal(alloc.capValue, 1000);
+  assert.equal(alloc.capUnit, "requests");
+});