diff --git a/tests/plugins/TopsyTurvy/basic/common.h b/tests/plugins/TopsyTurvy/basic/common.h
new file mode 100644
index 00000000..dcfcc35b
--- /dev/null
+++ b/tests/plugins/TopsyTurvy/basic/common.h
@@ -0,0 +1,27 @@
+// -*- mode: c++ -*-
+
+/* Kaleidoscope - Firmware for computer input devices
+ * 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/>.
+ */
+
+#pragma once
+
+#include <cstdint>
+
+namespace kaleidoscope {
+namespace testing {
+
+}  // namespace testing
+}  // namespace kaleidoscope
diff --git a/tests/plugins/TopsyTurvy/basic/sketch.ino b/tests/plugins/TopsyTurvy/basic/sketch.ino
new file mode 100644
index 00000000..ad1cb607
--- /dev/null
+++ b/tests/plugins/TopsyTurvy/basic/sketch.ino
@@ -0,0 +1,51 @@
+/* -*- 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-TopsyTurvy.h>
+
+#include "./common.h"
+
+// *INDENT-OFF*
+KEYMAPS(
+    [0] = KEYMAP_STACKED
+    (
+        TOPSY(1), TOPSY(2), ___, ___, ___, ___, ___,
+        Key_A, Key_B, ___, ___, ___, ___, ___,
+        Key_LeftShift, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___,
+        ___,
+
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___,
+        ___
+    ),
+)
+// *INDENT-ON*
+
+KALEIDOSCOPE_INIT_PLUGINS(TopsyTurvy);
+
+void setup() {
+  Kaleidoscope.setup();
+}
+
+void loop() {
+  Kaleidoscope.loop();
+}
diff --git a/tests/plugins/TopsyTurvy/basic/test.ktest b/tests/plugins/TopsyTurvy/basic/test.ktest
new file mode 100644
index 00000000..b2ca7b89
--- /dev/null
+++ b/tests/plugins/TopsyTurvy/basic/test.ktest
@@ -0,0 +1,47 @@
+VERSION 1
+
+KEYSWITCH TOPSY_1  0 0
+KEYSWITCH TOPSY_2  0 1
+KEYSWITCH A        1 0
+KEYSWITCH B        1 1
+KEYSWITCH LSHIFT   2 0
+
+# ==============================================================================
+NAME TopsyTurvy without shift
+
+RUN 5 ms
+PRESS TOPSY_1
+RUN 1 cycle
+EXPECT keyboard-report Key_LeftShift # The report should contain `shift`
+EXPECT keyboard-report Key_LeftShift Key_1 # The report should contain `shift` + `1`
+RUN 5 ms
+RELEASE TOPSY_1
+RUN 1 cycle
+EXPECT keyboard-report Key_LeftShift # The report should contain `shift`
+EXPECT keyboard-report empty # Report should be empty
+
+# ==============================================================================
+NAME TopsyTurvy with shift
+
+RUN 5 ms
+PRESS LSHIFT
+RUN 1 cycle
+EXPECT keyboard-report Key_LeftShift # The report should contain `shift`
+RUN 5 ms
+PRESS TOPSY_1
+RUN 1 cycle
+EXPECT keyboard-report empty # Report should be empty
+EXPECT keyboard-report Key_1 # The report should contain only `1`
+RUN 5 ms
+RELEASE TOPSY_1
+RUN 1 cycle
+EXPECT keyboard-report Key_LeftShift Key_1 # The report should contain `shift` + `1`
+# Really the report above should be empty, but it seems to work okay in master
+# like this, and it will get fixed if and when Kaleidoscope becomes
+# event-driven.
+# EXPECT keyboard-report empty # Report should be empty
+EXPECT keyboard-report Key_LeftShift # The report should contain `shift`
+RUN 5 ms
+RELEASE LSHIFT
+RUN 1 cycle
+EXPECT keyboard-report empty # Report should be empty