1 files changed, 151 insertions, 0 deletions
diff --git a/tests/unit_node/timers_test.ts b/tests/unit_node/timers_test.ts
index 868ba21d6..c7dc30bbb 100644
--- a/tests/unit_node/timers_test.ts
+++ b/tests/unit_node/timers_test.ts
@@ -3,6 +3,7 @@
 import { assert, fail } from "@std/assert";
 import * as timers from "node:timers";
 import * as timersPromises from "node:timers/promises";
+import { assertEquals } from "@std/assert";
 
 Deno.test("[node/timers setTimeout]", () => {
   {
@@ -108,3 +109,153 @@ Deno.test("[node/timers setImmediate returns Immediate object]", () => {
   imm.hasRef();
   clearImmediate(imm);
 });
+
+Deno.test({
+  name: "setInterval yields correct values at expected intervals",
+  async fn() {
+    // Test configuration
+    const CONFIG = {
+      expectedValue: 42,
+      intervalMs: 100,
+      iterations: 3,
+      tolerancePercent: 10,
+    };
+
+    const { setInterval } = timersPromises;
+    const results: Array<{ value: number; timestamp: number }> = [];
+    const startTime = Date.now();
+
+    const iterator = setInterval(CONFIG.intervalMs, CONFIG.expectedValue);
+
+    for await (const value of iterator) {
+      results.push({
+        value,
+        timestamp: Date.now(),
+      });
+      if (results.length === CONFIG.iterations) {
+        break;
+      }
+    }
+
+    const values = results.map((r) => r.value);
+    assertEquals(
+      values,
+      Array(CONFIG.iterations).fill(CONFIG.expectedValue),
+      `Each iteration should yield ${CONFIG.expectedValue}`,
+    );
+
+    const intervals = results.slice(1).map((result, index) => ({
+      interval: result.timestamp - results[index].timestamp,
+      iterationNumber: index + 1,
+    }));
+
+    const toleranceMs = (CONFIG.tolerancePercent / 100) * CONFIG.intervalMs;
+    const expectedRange = {
+      min: CONFIG.intervalMs - toleranceMs,
+      max: CONFIG.intervalMs + toleranceMs,
+    };
+
+    intervals.forEach(({ interval, iterationNumber }) => {
+      const isWithinTolerance = interval >= expectedRange.min &&
+        interval <= expectedRange.max;
+
+      assertEquals(
+        isWithinTolerance,
+        true,
+        `Iteration ${iterationNumber}: Interval ${interval}ms should be within ` +
+          `${expectedRange.min}ms and ${expectedRange.max}ms ` +
+          `(${CONFIG.tolerancePercent}% tolerance of ${CONFIG.intervalMs}ms)`,
+      );
+    });
+
+    const totalDuration = results[results.length - 1].timestamp - startTime;
+    const expectedDuration = CONFIG.intervalMs * CONFIG.iterations;
+    const isDurationReasonable =
+      totalDuration >= (expectedDuration - toleranceMs) &&
+      totalDuration <= (expectedDuration + toleranceMs);
+
+    assertEquals(
+      isDurationReasonable,
+      true,
+      `Total duration ${totalDuration}ms should be close to ${expectedDuration}ms ` +
+        `(within ${toleranceMs}ms tolerance)`,
+    );
+
+    const timestamps = results.map((r) => r.timestamp);
+    const areTimestampsOrdered = timestamps.every((timestamp, i) =>
+      i === 0 || timestamp > timestamps[i - 1]
+    );
+
+    assertEquals(
+      areTimestampsOrdered,
+      true,
+      "Timestamps should be strictly increasing",
+    );
+  },
+});
+
+Deno.test({
+  name: "setInterval with AbortSignal stops after expected duration",
+  async fn() {
+    const INTERVAL_MS = 500;
+    const TOTAL_DURATION_MS = 3000;
+    const TOLERANCE_MS = 500;
+
+    const abortController = new AbortController();
+    const { setInterval } = timersPromises;
+
+    // Set up abort after specified duration
+    const abortTimeout = timers.setTimeout(() => {
+      abortController.abort();
+    }, TOTAL_DURATION_MS);
+
+    // Track iterations and timing
+    const startTime = Date.now();
+    const iterations: number[] = [];
+
+    try {
+      for await (
+        const _timestamp of setInterval(INTERVAL_MS, undefined, {
+          signal: abortController.signal,
+        })
+      ) {
+        iterations.push(Date.now() - startTime);
+      }
+    } catch (error) {
+      if (error instanceof Error && error.name !== "AbortError") {
+        throw error;
+      }
+    } finally {
+      timers.clearTimeout(abortTimeout);
+    }
+
+    // Validate timing
+    const totalDuration = iterations[iterations.length - 1];
+    const isWithinTolerance =
+      totalDuration >= (TOTAL_DURATION_MS - TOLERANCE_MS) &&
+      totalDuration <= (TOTAL_DURATION_MS + TOLERANCE_MS);
+
+    assertEquals(
+      isWithinTolerance,
+      true,
+      `Total duration ${totalDuration}ms should be within ±${TOLERANCE_MS}ms of ${TOTAL_DURATION_MS}ms`,
+    );
+
+    // Validate interval consistency
+    const intervalDeltas = iterations.slice(1).map((time, i) =>
+      time - iterations[i]
+    );
+
+    intervalDeltas.forEach((delta, i) => {
+      const isIntervalValid = delta >= (INTERVAL_MS - 50) &&
+        delta <= (INTERVAL_MS + 50);
+      assertEquals(
+        isIntervalValid,
+        true,
+        `Interval ${
+          i + 1
+        } duration (${delta}ms) should be within ±50ms of ${INTERVAL_MS}ms`,
+      );
+    });
+  },
+});