diff --git a/src/test/kotlin/kestrel/WindowFunctionTest.kt b/src/test/kotlin/kestrel/WindowFunctionTest.kt
index 60a8253..1145bbb 100644
--- a/src/test/kotlin/kestrel/WindowFunctionTest.kt
+++ b/src/test/kotlin/kestrel/WindowFunctionTest.kt
@@ -304,3 +304,161 @@ class WindowFunctionTest {
         )
     }
 
+    @Test
+    fun lagPastThePartitionEdgeFallsBackToTheDefaultExpressionInsteadOfNull() {
+        seed()
+        val result = select(
+            "SELECT id, LAG(salary, 1, 0) OVER (PARTITION BY deptId ORDER BY salary DESC) AS prev " +
+                "FROM employees ORDER BY id ASC"
+        )
+        assertEquals(
+            listOf(0L, 400L, 400L, 0L, 200L, 200L),
+            result.rows.map { (it[1] as Value.IntegerValue).value }
+        )
+    }
+
+    @Test
+    fun lagOffsetMustNotBeNegative() {
+        seed()
+        val error = assertFailsWith<KestrelException> {
+            run("SELECT LAG(salary, -1) OVER (ORDER BY id) FROM employees")
+        }
+        assertTrue(error.message!!.contains("negative"), error.message!!)
+    }
+
+    @Test
+    fun lagOffsetMustBeAnInteger() {
+        seed()
+        val error = assertFailsWith<KestrelException> {
+            run("SELECT LAG(salary, 1.5) OVER (ORDER BY id) FROM employees")
+        }
+        assertTrue(error.message!!.contains("integer"), error.message!!)
+    }
+
+    @Test
+    fun firstValueReturnsTheFirstRowsValueForEveryRowInThePartition() {
+        seed()
+        val result = select(
+            "SELECT id, FIRST_VALUE(salary) OVER (PARTITION BY deptId ORDER BY salary DESC) AS top " +
+                "FROM employees ORDER BY id ASC"
+        )
+        assertEquals(listOf(400L, 400L, 400L, 200L, 200L, 200L), result.rows.map { (it[1] as Value.IntegerValue).value })
+    }
+
+    @Test
+    fun lastValueSharesOneValuePerPeerGroupRatherThanTheWholePartition() {
+        seed()
+        val result = select(
+            "SELECT id, LAST_VALUE(salary) OVER (PARTITION BY deptId ORDER BY salary DESC) AS lv " +
+                "FROM employees ORDER BY id ASC"
+        )
+        assertEquals(listOf(400L, 400L, 300L, 200L, 200L, 100L), result.rows.map { (it[1] as Value.IntegerValue).value })
+    }
+
+    @Test
+    fun lastValueWithoutOverOrderByUsesTheWholePartitionsLastRow() {
+        seed()
+        val result = select(
+            "SELECT id, LAST_VALUE(salary) OVER (PARTITION BY deptId) AS lv FROM employees ORDER BY id ASC"
+        )
+        assertEquals(listOf(300L, 300L, 300L, 100L, 100L, 100L), result.rows.map { (it[1] as Value.IntegerValue).value })
+    }
+
+    @Test
+    fun ntileSplitsEachPartitionIntoAsEvenBucketsAsPossible() {
+        seed()
+        val result = select(
+            "SELECT id, NTILE(2) OVER (PARTITION BY deptId ORDER BY salary DESC) AS bucket " +
+                "FROM employees ORDER BY id ASC"
+        )
+        assertEquals(listOf(1L, 1L, 2L, 1L, 1L, 2L), result.rows.map { (it[1] as Value.IntegerValue).value })
+    }
+
+    @Test
+    fun ntileWithMoreBucketsThanRowsLeavesTheHighestBucketsUnused() {
+        seed()
+        val result = select(
+            "SELECT id, NTILE(5) OVER (PARTITION BY deptId ORDER BY salary DESC) AS bucket " +
+                "FROM employees ORDER BY id ASC"
+        )
+        assertEquals(listOf(1L, 2L, 3L, 1L, 2L, 3L), result.rows.map { (it[1] as Value.IntegerValue).value })
+    }
+
+    @Test
+    fun ntileBucketCountMustBePositive() {
+        seed()
+        val error = assertFailsWith<KestrelException> {
+            run("SELECT NTILE(0) OVER (ORDER BY id) FROM employees")
+        }
+        assertTrue(error.message!!.contains("positive"), error.message!!)
+    }
+
+    @Test
+    fun ntileBucketCountMustBeAnInteger() {
+        seed()
+        val error = assertFailsWith<KestrelException> {
+            run("SELECT NTILE(1.5) OVER (ORDER BY id) FROM employees")
+        }
+        assertTrue(error.message!!.contains("integer"), error.message!!)
+    }
+
+    @Test
+    fun windowFunctionNestedInsideLagsOffsetIsRejected() {
+        seed()
+        val error = assertFailsWith<KestrelException> {
+            run("SELECT LAG(salary, ROW_NUMBER() OVER (ORDER BY id)) OVER (ORDER BY id) FROM employees")
+        }
+        assertTrue(error.message!!.contains("nested"), error.message!!)
+    }
+
+    @Test
+    fun explicitRowsFrameProducesAMovingAverageInsteadOfARunningTotal() {
+        seed()
+        val result = select(
+            "SELECT id, SUM(salary) OVER (PARTITION BY deptId ORDER BY id ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) AS s " +
+                "FROM employees ORDER BY id ASC"
+        )
+        assertEquals(
+            listOf(400L, 800L, 700L, 200L, 400L, 300L),
+            result.rows.map { (it[1] as Value.IntegerValue).value }
+        )
+    }
+
+    @Test
+    fun rowsBetweenCurrentRowAndFollowingLooksForward() {
+        seed()
+        val result = select(
+            "SELECT id, SUM(salary) OVER (PARTITION BY deptId ORDER BY id ROWS BETWEEN CURRENT ROW AND 1 FOLLOWING) AS s " +
+                "FROM employees ORDER BY id ASC"
+        )
+        assertEquals(
+            listOf(800L, 700L, 300L, 400L, 300L, 100L),
+            result.rows.map { (it[1] as Value.IntegerValue).value }
+        )
+    }
+
+    @Test
+    fun rowsBetweenUnboundedPrecedingAndCurrentRowMatchesTheImplicitDefaultOnAUniqueOrderKey() {
+        seed()
+        val explicit = select(
+            "SELECT id, SUM(salary) OVER (ORDER BY id ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS s " +
+                "FROM employees ORDER BY id ASC"
+        )
+        val implicit = select("SELECT id, SUM(salary) OVER (ORDER BY id) AS s FROM employees ORDER BY id ASC")
+        assertEquals(implicit.rows, explicit.rows)
+    }
+
+    @Test
+    fun frameEntirelyPastThePartitionEdgeAggregatesToNullAndCountsZero() {
+        seed()
+        val result = select(
+            "SELECT id, SUM(salary) OVER (PARTITION BY deptId ORDER BY id ROWS BETWEEN 5 FOLLOWING AND 9 FOLLOWING) AS s, " +
+                "COUNT(*) OVER (PARTITION BY deptId ORDER BY id ROWS BETWEEN 5 FOLLOWING AND 9 FOLLOWING) AS c " +
+                "FROM employees WHERE deptId = 1 ORDER BY id ASC"
+        )
+        assertEquals(
+            listOf(listOf(int(1), Value.NullValue, int(0)), listOf(int(2), Value.NullValue, int(0)), listOf(int(3), Value.NullValue, int(0))),
+            result.rows
+        )
+    }
+