diff --git a/tests/testRandomTick.cpp b/tests/testRandomTick.cpp
new file mode 100644
index 0000000..719827d
--- /dev/null
+++ b/tests/testRandomTick.cpp
@@ -0,0 +1,75 @@
+#include "testHarness.h"
+#include "vf/RandomTick.h"
+#include "vf/Chunk.h"
+
+using namespace vf;
+
+VF_TEST(sampleReturnsConfiguredCountInBounds) {
+    RandomTick selector(123u, 5);
+    std::vector<Vec3i> draw = selector.sampleLocal({0, 0, 0}, 0);
+    CHECK_EQ(draw.size(), static_cast<std::size_t>(5));
+    for (const Vec3i& cell : draw) {
+        CHECK(cell.x >= 0 && cell.x < chunkSize);
+        CHECK(cell.y >= 0 && cell.y < chunkSize);
+        CHECK(cell.z >= 0 && cell.z < chunkSize);
+    }
+}
+
+VF_TEST(zeroTicksPerChunkYieldsEmptyDraw) {
+    RandomTick selector(1u, 0);
+    CHECK_EQ(selector.ticksPerChunk(), 0);
+    CHECK(selector.sampleLocal({2, 3, 4}, 9).empty());
+}
+
+VF_TEST(globalDrawIsLocalDrawOffsetByChunkOrigin) {
+    RandomTick selector(77u, 6);
+    Vec3i coord{1, -2, 3};
+    long long tick = 41;
+    std::vector<Vec3i> local = selector.sampleLocal(coord, tick);
+    std::vector<Vec3i> global = selector.sampleGlobal(coord, tick);
+    CHECK_EQ(local.size(), global.size());
+    for (std::size_t i = 0; i < local.size(); ++i) {
+        CHECK_EQ(global[i].x, local[i].x + coord.x * chunkSize);
+        CHECK_EQ(global[i].y, local[i].y + coord.y * chunkSize);
+        CHECK_EQ(global[i].z, local[i].z + coord.z * chunkSize);
+    }
+}
+
+VF_TEST(sameSeedReplaysIdenticalStream) {
+    RandomTick a(2024u, 4);
+    RandomTick b(2024u, 4);
+    for (int cx = -2; cx <= 2; ++cx)
+        for (long long t = 0; t < 8; ++t)
+            CHECK(a.sampleLocal({cx, 0, 0}, t) == b.sampleLocal({cx, 0, 0}, t));
+}
+
+VF_TEST(theTickNumberChangesTheDraw) {
+    RandomTick selector(5u, 4);
+    Vec3i coord{0, 0, 0};
+    bool sawDifference = false;
+    std::vector<Vec3i> first = selector.sampleLocal(coord, 0);
+    for (long long t = 1; t < 16 && !sawDifference; ++t)
+        if (selector.sampleLocal(coord, t) != first) sawDifference = true;
+    CHECK(sawDifference);
+}
+
+VF_TEST(theSeedChangesTheDraw) {
+    RandomTick a(1u, 6);
+    RandomTick b(2u, 6);
+    CHECK(a.sampleLocal({0, 0, 0}, 0) != b.sampleLocal({0, 0, 0}, 0));
+}
+
+VF_TEST(theChunkCoordinateChangesTheDraw) {
+    RandomTick selector(9u, 6);
+    CHECK(selector.sampleLocal({0, 0, 0}, 3) != selector.sampleLocal({1, 0, 0}, 3));
+    CHECK(selector.sampleLocal({0, 0, 0}, 3) != selector.sampleLocal({0, 0, 1}, 3));
+}
+
+VF_TEST(hashDistinguishesIndicesAndIsStable) {
+    RandomTick selector(31u, 4);
+    Vec3i coord{4, 1, -3};
+    uint64_t first = selector.hash(coord, 10, 0);
+    uint64_t second = selector.hash(coord, 10, 1);
+    CHECK(first != second);
+    CHECK_EQ(first, selector.hash(coord, 10, 0));
+}