diff --git a/packages/backend-core/src/sql/tests/utils.spec.ts b/packages/backend-core/src/sql/tests/utils.spec.ts
new file mode 100644
index 0000000000..847e9c674c
--- /dev/null
+++ b/packages/backend-core/src/sql/tests/utils.spec.ts
@@ -0,0 +1,23 @@
+import { isInvalidISODateString } from "../utils"
+
+describe("isInvalidISODateString", () => {
+  it("accepts a valid ISO date without a time", () => {
+    const invalid = isInvalidISODateString("2013-02-01")
+    expect(invalid).toEqual(false)
+  })
+
+  it("accepts a valid ISO date with a time", () => {
+    const invalid = isInvalidISODateString("2013-02-01T01:23:45Z")
+    expect(invalid).toEqual(false)
+  })
+
+  it("accepts a valid ISO date with a time and millis", () => {
+    const invalid = isInvalidISODateString("2013-02-01T01:23:45.678Z")
+    expect(invalid).toEqual(false)
+  })
+
+  it("rejects an invalid ISO date", () => {
+    const invalid = isInvalidISODateString("2013-523-814T444:22:11Z")
+    expect(invalid).toEqual(true)
+  })
+})