diff --git a/tests/features/layers/activation-order/sketch.ino b/tests/features/layers/activation-order/sketch.ino
new file mode 100644
index 00000000..cf592980
--- /dev/null
+++ b/tests/features/layers/activation-order/sketch.ino
@@ -0,0 +1,98 @@
+/* -*- mode: c++ -*-
+ * Copyright (C) 2020  Keyboard.io, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "Kaleidoscope.h"
+
+#include "Kaleidoscope-Macros.h"
+
+// *INDENT-OFF*
+
+KEYMAPS(
+  [0] = KEYMAP_STACKED
+  (
+    Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A
+   ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A
+   ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A
+   ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A
+   ,Key_A ,Key_A ,Key_A ,M(0)
+   ,ShiftToLayer(1)
+
+   ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A
+   ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A
+          ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A
+   ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A ,Key_A
+   ,Key_A ,Key_A ,Key_A ,Key_A
+   ,ShiftToLayer(2)
+  ),
+
+  [1] =  KEYMAP_STACKED
+  (
+    Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B
+   ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B
+   ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B
+   ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B
+   ,Key_B ,Key_B ,Key_B ,Key_B
+   ,___
+
+   ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B
+   ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B
+          ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B
+   ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B ,Key_B
+   ,Key_B ,Key_B ,Key_B ,Key_B
+   ,___
+  ),
+
+  [2] =  KEYMAP_STACKED
+  (
+    Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C
+   ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C
+   ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C
+   ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C
+   ,Key_C ,Key_C ,Key_C ,Key_C
+   ,___
+
+   ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C
+   ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C
+          ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C
+   ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C ,Key_C
+   ,Key_C ,Key_C ,Key_C ,Key_C
+   ,___
+  )
+) // KEYMAPS(
+
+// *INDENT-ON*
+
+KALEIDOSCOPE_INIT_PLUGINS(Macros);
+
+const macro_t *macroAction(uint8_t macroIndex, uint8_t keyState) {
+  switch (macroIndex) {
+  case 0:
+    if (keyToggledOn(keyState))
+      Layer.deactivate(0);
+    else
+      Layer.activate(0);
+    break;
+  }
+  return MACRO_NONE;
+}
+
+void setup() {
+  Kaleidoscope.setup();
+}
+
+void loop() {
+  Kaleidoscope.loop();
+}
diff --git a/tests/features/layers/activation-order/test/testcase.cpp b/tests/features/layers/activation-order/test/testcase.cpp
new file mode 100644
index 00000000..31ab26c1
--- /dev/null
+++ b/tests/features/layers/activation-order/test/testcase.cpp
@@ -0,0 +1,177 @@
+/* -*- mode: c++ -*-
+ * Copyright (C) 2020  Keyboard.io, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "testing/setup-googletest.h"
+
+SETUP_GOOGLETEST();
+
+namespace kaleidoscope {
+namespace testing {
+namespace {
+
+using ::testing::IsEmpty;
+
+class LayerActivationOrder : public VirtualDeviceTest {
+ public:
+  void SingleKeyTest(Key k) {
+    sim_.Press(0, 0); // k
+    auto state = RunCycle();
+
+    ASSERT_EQ(state->HIDReports()->Keyboard().size(), 1);
+    EXPECT_THAT(
+      state->HIDReports()->Keyboard(0).ActiveKeycodes(),
+      Contains(k));
+
+    sim_.Release(0, 0);  // k
+    state = RunCycle();
+
+    ASSERT_EQ(state->HIDReports()->Keyboard().size(), 1);
+    EXPECT_THAT(
+      state->HIDReports()->Keyboard(0).ActiveKeycodes(),
+      IsEmpty());
+
+    state = RunCycle();
+
+    // 2 cycles after releasing k
+    EXPECT_EQ(state->HIDReports()->Keyboard().size(), 0);
+  }
+};
+
+TEST_F(LayerActivationOrder, BaseLayerHasNotRegressed) {
+  SingleKeyTest(Key_A);
+}
+
+TEST_F(LayerActivationOrder, ShifToLayerOne) {
+  // Pressing (3,6) shifts to Layer 1, and we stay there until release.
+
+  sim_.Press(3, 6); // ShiftToLayer(1)
+  auto state = RunCycle();
+
+  SingleKeyTest(Key_B);
+
+  // Releasing (3,6) gets us back to the base layer
+  sim_.Release(3, 6); // ShiftToLayer(1)
+  state = RunCycle();
+
+  SingleKeyTest(Key_A);
+}
+
+TEST_F(LayerActivationOrder, ShiftingWithCaching) {
+  // Pressing (0, 0) will activate A
+  sim_.Press(0, 0);
+  auto state = RunCycle();
+
+  ASSERT_EQ(state->HIDReports()->Keyboard().size(), 1);
+  EXPECT_THAT(
+    state->HIDReports()->Keyboard(0).ActiveKeycodes(),
+    Contains(Key_A));
+
+  // Pressing (3, 6) will switch to Layer 1
+  sim_.Press(3, 6);
+  state = RunCycle();
+
+  // ...since we're still pressing (0, 0), and there was no change in the HID
+  // states, we shouldn't emit a report.
+  ASSERT_EQ(state->HIDReports()->Keyboard().size(), 0);
+
+  // Pressing (0, 1), the report shall contain 'A' _and_ 'B'.
+  sim_.Press(0, 1);
+  state = RunCycle();
+
+  ASSERT_EQ(state->HIDReports()->Keyboard().size(), 1);
+  EXPECT_THAT(
+    state->HIDReports()->Keyboard(0).ActiveKeycodes(),
+    Contains(Key_A));
+  EXPECT_THAT(
+    state->HIDReports()->Keyboard(0).ActiveKeycodes(),
+    Contains(Key_B));
+
+  // Releasing (0, 0), the report should now contain B only
+  sim_.Release(0, 0);
+  state = RunCycle();
+
+  ASSERT_EQ(state->HIDReports()->Keyboard().size(), 1);
+  EXPECT_THAT(
+    state->HIDReports()->Keyboard(0).ActiveKeycodes(),
+    Contains(Key_B));
+
+  // Release (0, 1)
+  sim_.Release(0, 1);
+  state = RunCycle();
+
+  // Test B in isolation again
+  SingleKeyTest(Key_B);
+
+  // Release the layer key as well.
+  sim_.Release(3, 6);
+  state = RunCycle();
+
+  ASSERT_EQ(state->HIDReports()->Keyboard().size(), 0);
+}
+
+TEST_F(LayerActivationOrder, Ordering) {
+  // Pressing (3, 9) will switch to Layer 2
+  sim_.Press(3, 9);
+  auto state = RunCycle();
+
+  // Pressing (0, 0) will activate 'C'
+  sim_.Press(0, 0);
+  state = RunCycle();
+
+  ASSERT_EQ(state->HIDReports()->Keyboard().size(), 1);
+  EXPECT_THAT(
+    state->HIDReports()->Keyboard(0).ActiveKeycodes(),
+    Contains(Key_C));
+
+  // Pressing (3, 6) will activate Layer 1
+  sim_.Press(3, 6);
+  state = RunCycle();
+
+  // Pressing (0, 1) will activate 'B' now, due to activation ordering.
+  sim_.Press(0, 1);
+  state = RunCycle();
+
+  ASSERT_EQ(state->HIDReports()->Keyboard().size(), 1);
+  EXPECT_THAT(
+    state->HIDReports()->Keyboard(0).ActiveKeycodes(),
+    Contains(Key_C));
+  EXPECT_THAT(
+    state->HIDReports()->Keyboard(0).ActiveKeycodes(),
+    Contains(Key_B));
+
+  sim_.Release(0, 0);
+  sim_.Release(0, 1);
+  sim_.Release(3, 6);
+  sim_.Release(3, 9);
+  state = RunCycle();
+}
+
+TEST_F(LayerActivationOrder, LayerZero) {
+  sim_.Press(3, 7); // Macro#0: Layer.deactivate(0)
+  auto state = RunCycle();
+
+  sim_.Press(0, 0); // A
+  state = RunCycle();
+
+  ASSERT_EQ(state->HIDReports()->Keyboard().size(), 1);
+  EXPECT_THAT(
+    state->HIDReports()->Keyboard(0).ActiveKeycodes(),
+    Contains(Key_A));
+}
+
+}  // namespace
+}  // namespace testing
+}  // namespace kaleidoscope