chore: Add basic tests for Studio's layer manipulation (#3164)

chore: Add test behaviors for Studio testing

chore: Add basic tests for studio layer adjustment

chore: Fixes from code review

app/include/zmk/keymap.h

@@ -11,11 +11,12 @@
 #include <zephyr/devicetree.h>
 
 #define ZMK_KEYMAP_LAYERS_FOREACH(_fn)                                                             \
-    COND_CODE_1(IS_ENABLED(CONFIG_ZMK_STUDIO), (DT_FOREACH_CHILD(DT_INST(0, zmk_keymap), _fn)),    \
+    COND_CODE_1(IS_ENABLED(CONFIG_ZMK_KEYMAP_LAYER_REORDERING),                                    \
+                (DT_FOREACH_CHILD(DT_INST(0, zmk_keymap), _fn)),                                   \
                 (DT_FOREACH_CHILD_STATUS_OKAY(DT_INST(0, zmk_keymap), _fn)))
 
 #define ZMK_KEYMAP_LAYERS_FOREACH_SEP(_fn, _sep)                                                   \
-    COND_CODE_1(IS_ENABLED(CONFIG_ZMK_STUDIO),                                                     \
+    COND_CODE_1(IS_ENABLED(CONFIG_ZMK_KEYMAP_LAYER_REORDERING),                                    \
                 (DT_FOREACH_CHILD_SEP(DT_INST(0, zmk_keymap), _fn, _sep)),                         \
                 (DT_FOREACH_CHILD_STATUS_OKAY_SEP(DT_INST(0, zmk_keymap), _fn, _sep)))
 

app/module/CMakeLists.txt

@@ -1,4 +1,5 @@
 zephyr_include_directories(include)
 
 add_subdirectory(drivers)
+add_subdirectory(test-behaviors)
 add_subdirectory(lib)

app/module/Kconfig

@@ -1,3 +1,4 @@
 
 rsource "drivers/Kconfig"
-rsource "lib/Kconfig"
+rsource "lib/Kconfig"
+rsource "test-behaviors/Kconfig"

app/module/dts/bindings/test-behaviors/zmk,behavior_add_layer.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2025 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Layer Adder Behavior
+
+compatible: "zmk,behavior-add-layer"
+
+include: zero_param.yaml

app/module/dts/bindings/test-behaviors/zmk,behavior_move_layer.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2025 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Layer Mover Behavior
+
+compatible: "zmk,behavior-move-layer"
+
+include: two_param.yaml

app/module/dts/bindings/test-behaviors/zmk,behavior_remove_layer.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2025 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Layer Remover Behavior
+
+compatible: "zmk,behavior-remove-layer"
+
+include: one_param.yaml

app/module/dts/bindings/test-behaviors/zmk,behavior_set_layer_binding_at_idx.yaml

@@ -0,0 +1,13 @@
+# Copyright (c) 2025 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Layer Binding Setter Behavior
+
+compatible: "zmk,behavior-set-layer-binding-at-idx"
+
+include: two_param.yaml
+
+properties:
+  bindings:
+    type: phandle-array
+    required: true

app/module/test-behaviors/CMakeLists.txt

@@ -0,0 +1,6 @@
+if (((NOT CONFIG_ZMK_SPLIT) OR CONFIG_ZMK_SPLIT_ROLE_CENTRAL) AND CONFIG_ZMK_TEST_BEHAVIORS)
+  target_sources(app PRIVATE behavior_add_layer.c)
+  target_sources(app PRIVATE behavior_move_layer.c)
+  target_sources(app PRIVATE behavior_remove_layer.c)
+  target_sources(app PRIVATE behavior_set_layer_binding_at_idx.c)
+endif()

app/module/test-behaviors/Kconfig

@@ -0,0 +1,2 @@
+config ZMK_TEST_BEHAVIORS
+    bool "Include behaviors used for testing purposes"

app/module/test-behaviors/behavior_add_layer.c

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2025 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_behavior_add_layer
+
+#include <zephyr/device.h>
+#include <drivers/behavior.h>
+#include <zephyr/logging/log.h>
+
+#include <zmk/keymap.h>
+#include <zmk/behavior.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#if (IS_ENABLED(CONFIG_ZMK_KEYMAP_LAYER_REORDERING)) && (DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT))
+
+static int on_add_layer_binding_pressed(struct zmk_behavior_binding *binding,
+                                        struct zmk_behavior_binding_event event) {
+    int new_layer = zmk_keymap_add_layer();
+    if (new_layer >= 0) {
+        LOG_DBG("Added layer %d", new_layer);
+        return 0;
+    }
+    switch (new_layer) {
+    case -ENOSPC:
+        LOG_ERR("No more layers can be added. Out of memory.");
+        return -ENOSPC;
+    default:
+        LOG_ERR("Unknown error adding layer: %d", new_layer);
+        return new_layer;
+    }
+}
+
+static int on_add_layer_binding_released(struct zmk_behavior_binding *binding,
+                                         struct zmk_behavior_binding_event event) {
+    return 0;
+}
+
+static const struct behavior_driver_api behavior_add_layer_driver_api = {
+    .binding_pressed = on_add_layer_binding_pressed,
+    .binding_released = on_add_layer_binding_released};
+
+BEHAVIOR_DT_INST_DEFINE(0, NULL, NULL, NULL, NULL, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,
+                        &behavior_add_layer_driver_api);
+
+#endif // IS_ENABLED(CONFIG_ZMK_KEYMAP_LAYER_REORDERING) AND
+       // DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)

app/module/test-behaviors/behavior_move_layer.c

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2025 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_behavior_move_layer
+
+#include <zephyr/device.h>
+#include <drivers/behavior.h>
+#include <zephyr/logging/log.h>
+
+#include <zmk/keymap.h>
+#include <zmk/behavior.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#if (IS_ENABLED(CONFIG_ZMK_KEYMAP_LAYER_REORDERING)) && (DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT))
+
+static int on_move_layer_binding_pressed(struct zmk_behavior_binding *binding,
+                                         struct zmk_behavior_binding_event event) {
+    int result = zmk_keymap_move_layer(binding->param1, binding->param2);
+
+    if (result < 0) {
+        LOG_ERR("Failed to move layer from index %d to index %d (err: %d)", binding->param1,
+                binding->param2, result);
+        return result;
+    }
+
+    LOG_DBG("Moved layer from index %d to index %d", binding->param1, binding->param2);
+    return 0;
+}
+
+static int on_move_layer_binding_released(struct zmk_behavior_binding *binding,
+                                          struct zmk_behavior_binding_event event) {
+    return 0;
+}
+
+static const struct behavior_driver_api behavior_move_layer_driver_api = {
+    .binding_pressed = on_move_layer_binding_pressed,
+    .binding_released = on_move_layer_binding_released};
+
+BEHAVIOR_DT_INST_DEFINE(0, NULL, NULL, NULL, NULL, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,
+                        &behavior_move_layer_driver_api);
+
+#endif // IS_ENABLED(CONFIG_ZMK_KEYMAP_LAYER_REORDERING) AND
+       // DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)

app/module/test-behaviors/behavior_remove_layer.c

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2025 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_behavior_remove_layer
+
+#include <zephyr/device.h>
+#include <drivers/behavior.h>
+#include <zephyr/logging/log.h>
+
+#include <zmk/keymap.h>
+#include <zmk/behavior.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#if (IS_ENABLED(CONFIG_ZMK_KEYMAP_LAYER_REORDERING)) && (DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT))
+
+static int on_remove_layer_binding_pressed(struct zmk_behavior_binding *binding,
+                                           struct zmk_behavior_binding_event event) {
+    int result = zmk_keymap_remove_layer(binding->param1);
+    if (result >= 0) {
+        LOG_DBG("Removed layer at index %d", binding->param1);
+        return 0;
+    }
+    switch (result) {
+    case -EINVAL:
+        LOG_ERR("Layer at index %d not found", binding->param1);
+        return -EINVAL;
+    default:
+        LOG_DBG("Unknown error removing layer at index %d: %d", binding->param1, result);
+        return result;
+    }
+}
+
+static int on_remove_layer_binding_released(struct zmk_behavior_binding *binding,
+                                            struct zmk_behavior_binding_event event) {
+    return 0;
+}
+
+static const struct behavior_driver_api behavior_remove_layer_driver_api = {
+    .binding_pressed = on_remove_layer_binding_pressed,
+    .binding_released = on_remove_layer_binding_released};
+
+BEHAVIOR_DT_INST_DEFINE(0, NULL, NULL, NULL, NULL, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,
+                        &behavior_remove_layer_driver_api);
+#endif // IS_ENABLED(CONFIG_ZMK_KEYMAP_LAYER_REORDERING) AND
+       // DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)

app/module/test-behaviors/behavior_set_layer_binding_at_idx.c

@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2025 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_behavior_set_layer_binding_at_idx
+
+#include <zephyr/device.h>
+#include <drivers/behavior.h>
+#include <zephyr/logging/log.h>
+
+#include <zmk/keymap.h>
+#include <zmk/behavior.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#if DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)
+
+struct behavior_set_layer_binding_at_idx_config {
+    size_t bindings_len;
+    struct zmk_behavior_binding *bindings;
+};
+
+struct behavior_set_layer_binding_at_idx_data {
+    size_t current_idx;
+};
+
+static int on_set_layer_binding_at_idx_binding_pressed(struct zmk_behavior_binding *binding,
+                                                       struct zmk_behavior_binding_event event) {
+    const struct device *dev = zmk_behavior_get_binding(binding->behavior_dev);
+    const struct behavior_set_layer_binding_at_idx_config *cfg = dev->config;
+    struct behavior_set_layer_binding_at_idx_data *data = dev->data;
+
+    if (cfg->bindings_len == 0) {
+        LOG_ERR("No bindings configured");
+        return -EINVAL;
+    }
+
+    struct zmk_behavior_binding *binding_to_set = &cfg->bindings[data->current_idx];
+
+    int result =
+        zmk_keymap_set_layer_binding_at_idx(binding->param1, binding->param2, *binding_to_set);
+
+    if (result < 0) {
+        LOG_ERR("Failed to set binding at layer %d, index %d (err: %d)", binding->param1,
+                binding->param2, result);
+        return result;
+    }
+
+    LOG_DBG("Set binding at layer %d, index %d to binding %zu/%zu", binding->param1,
+            binding->param2, data->current_idx + 1, cfg->bindings_len);
+
+    // Move to next binding, wrap around if at end
+    data->current_idx = (data->current_idx + 1) % cfg->bindings_len;
+
+    return 0;
+}
+
+static int on_set_layer_binding_at_idx_binding_released(struct zmk_behavior_binding *binding,
+                                                        struct zmk_behavior_binding_event event) {
+    return 0;
+}
+
+static const struct behavior_driver_api behavior_set_layer_binding_at_idx_driver_api = {
+    .binding_pressed = on_set_layer_binding_at_idx_binding_pressed,
+    .binding_released = on_set_layer_binding_at_idx_binding_released};
+
+static int behavior_set_layer_binding_at_idx_init(const struct device *dev) {
+    struct behavior_set_layer_binding_at_idx_data *data = dev->data;
+    data->current_idx = 0;
+    return 0;
+};
+
+#define _TRANSFORM_ENTRY(idx, node) ZMK_KEYMAP_EXTRACT_BINDING(idx, node)
+
+#define TRANSFORMED_BINDINGS(node)                                                                 \
+    {LISTIFY(DT_INST_PROP_LEN(node, bindings), _TRANSFORM_ENTRY, (, ), DT_DRV_INST(node))}
+
+#define SET_LAYER_BINDING_AT_IDX_INST(n)                                                           \
+    static struct behavior_set_layer_binding_at_idx_data                                           \
+        behavior_set_layer_binding_at_idx_data_##n = {};                                           \
+                                                                                                   \
+    static const struct zmk_behavior_binding                                                       \
+        behavior_set_layer_binding_at_idx_config_##n##_bindings[DT_INST_PROP_LEN(n, bindings)] =   \
+            TRANSFORMED_BINDINGS(n);                                                               \
+    static const struct behavior_set_layer_binding_at_idx_config                                   \
+        behavior_set_layer_binding_at_idx_config_##n = {                                           \
+            .bindings_len = DT_INST_PROP_LEN(n, bindings),                                         \
+            .bindings = behavior_set_layer_binding_at_idx_config_##n##_bindings};                  \
+                                                                                                   \
+    BEHAVIOR_DT_INST_DEFINE(n, behavior_set_layer_binding_at_idx_init, NULL,                       \
+                            &behavior_set_layer_binding_at_idx_data_##n,                           \
+                            &behavior_set_layer_binding_at_idx_config_##n, POST_KERNEL,            \
+                            CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,                                   \
+                            &behavior_set_layer_binding_at_idx_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(SET_LAYER_BINDING_AT_IDX_INST)
+
+#endif // DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)

app/run-test.sh

@@ -41,6 +41,12 @@ build_cmd="west build ${ZMK_SRC_DIR:+-s $ZMK_SRC_DIR} -d ${ZMK_BUILD_DIR}/tests/
     -b native_sim/native/64 -p -- -DCONFIG_ASSERT=y -DZMK_CONFIG="$(realpath $path)" \
     ${ZMK_EXTRA_MODULES:+-DZMK_EXTRA_MODULES="$(realpath ${ZMK_EXTRA_MODULES})"}"
 
+# Add extra cmake arguments from file if it exists
+if [ -f "$path/extra-cmake-args" ]; then
+    extra_args=$(cat "$path/extra-cmake-args" | tr '\n' ' ')
+    build_cmd="$build_cmd $extra_args"
+fi
+
 build_log_tmp="${ZMK_BUILD_DIR}/tmp/$testcase/build.log"
 build_log="${ZMK_BUILD_DIR}/tests/$testcase/build.log"
 mkdir -p $(dirname $build_log_tmp)

app/tests/studio/add-layer/basic/events.patterns

@@ -0,0 +1,4 @@
+s/.*on_add_layer_binding_pressed/add_layer/p
+s/.*on_set_layer_binding_at_idx_binding_pressed/set_layer_binding/p
+s/.*layer_changed/layer_changed/p
+s/.*hid_listener_keycode_//p

app/tests/studio/add-layer/basic/extra-cmake-args

@@ -0,0 +1,5 @@
+-DCONFIG_ZMK_BEHAVIOR_METADATA=y
+-DCONFIG_ZMK_BEHAVIOR_LOCAL_IDS=y
+-DCONFIG_ZMK_KEYMAP_LAYER_REORDERING=y
+-DCONFIG_ZMK_KEYMAP_SETTINGS_STORAGE=y
+-DCONFIG_SETTINGS=y

app/tests/studio/add-layer/basic/keycode_events.snapshot

@@ -0,0 +1,6 @@
+add_layer: Added layer 1
+set_layer_binding: Set binding at layer 1, index 0 to binding 1/2
+layer_changed: layer 1 state 1 locked 0
+pressed: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00
+released: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00
+layer_changed: layer 1 state 0 locked 0

app/tests/studio/add-layer/basic/native_sim.conf

@@ -0,0 +1 @@
+CONFIG_ZMK_TEST_BEHAVIORS=y

app/tests/studio/add-layer/basic/native_sim.keymap

@@ -0,0 +1,23 @@
+#include <dt-bindings/zmk/keys.h>
+#include <behaviors.dtsi>
+#include <dt-bindings/zmk/kscan_mock.h>
+#include "../behavior_keymap.dtsi"
+
+// Test adding a layer, setting a binding, activating it, and pressing the binding
+&kscan {
+    events = <
+    // add a new layer
+    ZMK_MOCK_PRESS(0,0,10)
+    ZMK_MOCK_RELEASE(0,0,10)
+    // set binding A at layer 1, position 0
+    ZMK_MOCK_PRESS(0,1,10)
+    ZMK_MOCK_RELEASE(0,1,10)
+    // activate layer 1 with momentary
+    ZMK_MOCK_PRESS(1,0,10)
+    // press position 0 on new layer (should be A)
+    ZMK_MOCK_PRESS(0,0,10)
+    ZMK_MOCK_RELEASE(0,0,10)
+    // release momentary layer 1
+    ZMK_MOCK_RELEASE(1,0,10)
+    >;
+};

app/tests/studio/add-layer/behavior_keymap.dtsi

@@ -0,0 +1,32 @@
+#include <dt-bindings/zmk/keys.h>
+#include <behaviors.dtsi>
+#include <dt-bindings/zmk/kscan_mock.h>
+
+/ {
+    behaviors {
+        add_layer: add_layer {
+            compatible = "zmk,behavior-add-layer";
+            #binding-cells = <0>;
+        };
+
+        set_binding: set_binding {
+            compatible = "zmk,behavior-set-layer-binding-at-idx";
+            #binding-cells = <2>;
+            bindings = <&kp A>, <&kp B>;
+        };
+    };
+
+    keymap {
+        compatible = "zmk,keymap";
+
+        default_layer {
+            bindings = <
+                &add_layer &set_binding 1 0
+                &mo 1 &kp B>;
+        };
+
+        layer_1 {
+            status = "reserved";
+        };
+    };
+};

app/tests/studio/move-layer/basic/events.patterns

@@ -0,0 +1,3 @@
+s/.*layer_changed/layer_changed/p
+s/.*hid_listener_keycode_//p
+s/.*on_move_layer_binding_pressed/move_layer/p

app/tests/studio/move-layer/basic/extra-cmake-args

@@ -0,0 +1,5 @@
+-DCONFIG_ZMK_BEHAVIOR_METADATA=y
+-DCONFIG_ZMK_BEHAVIOR_LOCAL_IDS=y
+-DCONFIG_ZMK_KEYMAP_LAYER_REORDERING=y
+-DCONFIG_ZMK_KEYMAP_SETTINGS_STORAGE=y
+-DCONFIG_SETTINGS=y

app/tests/studio/move-layer/basic/keycode_events.snapshot

@@ -0,0 +1,8 @@
+move_layer: Moved layer from index 1 to index 2
+layer_changed: layer 1 state 1 locked 0
+layer_changed: layer 2 state 1 locked 0
+pressed: usage_page 0x07 keycode 0x06 implicit_mods 0x00 explicit_mods 0x00
+released: usage_page 0x07 keycode 0x06 implicit_mods 0x00 explicit_mods 0x00
+layer_changed: layer 2 state 0 locked 0
+pressed: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00
+released: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00

app/tests/studio/move-layer/basic/native_sim.conf

@@ -0,0 +1 @@
+CONFIG_ZMK_TEST_BEHAVIORS=y

app/tests/studio/move-layer/basic/native_sim.keymap

@@ -0,0 +1,26 @@
+#include <dt-bindings/zmk/keys.h>
+#include <behaviors.dtsi>
+#include <dt-bindings/zmk/kscan_mock.h>
+#include "../behavior_keymap.dtsi"
+
+// Test moving a layer: swap layers 1 and 2, turn both on,
+// press transparent on layer 1 at index 2
+// which should fall through to layer 2 at index 1
+&kscan {
+    events = <
+    // move layer 1 to position 2 (effectively swapping layers 1 and 2)
+    ZMK_MOCK_PRESS(0,0,10)
+    ZMK_MOCK_RELEASE(0,0,10)
+    // activate layers 1 and 2
+    ZMK_MOCK_PRESS(1,0,10)
+    ZMK_MOCK_PRESS(1,1,10)
+    // press position 0,1 on layer 2 - should output C from layer 2 at index 1
+    ZMK_MOCK_PRESS(0,1,10)
+    ZMK_MOCK_RELEASE(0,1,10)
+    // release layer 2 (at index 1)
+    ZMK_MOCK_RELEASE(1,1,10)
+    // press position 0,1 again - should output A from default layer
+    ZMK_MOCK_PRESS(0,1,10)
+    ZMK_MOCK_RELEASE(0,1,10)
+    >;
+};

app/tests/studio/move-layer/behavior_keymap.dtsi

@@ -0,0 +1,34 @@
+#include <dt-bindings/zmk/keys.h>
+#include <behaviors.dtsi>
+#include <dt-bindings/zmk/kscan_mock.h>
+
+/ {
+    behaviors {
+        move_layer: move_layer {
+            compatible = "zmk,behavior-move-layer";
+            #binding-cells = <2>;
+        };
+    };
+
+    keymap {
+        compatible = "zmk,keymap";
+
+        default_layer {
+            bindings = <
+                &move_layer 1 2 &kp A
+                &mo 1 &mo 2>;
+        };
+
+        layer_1 {
+            bindings = <
+                &kp B &trans
+                &trans &trans>;
+        };
+
+        layer_2 {
+            bindings = <
+                &trans &kp C
+                &trans &trans>;
+        };
+    };
+};

app/tests/studio/remove-layer/basic/events.patterns

@@ -0,0 +1,3 @@
+s/.*layer_changed/layer_changed/p
+s/.*hid_listener_keycode_//p
+s/.*on_remove_layer_binding_pressed/remove_layer/p

app/tests/studio/remove-layer/basic/extra-cmake-args

@@ -0,0 +1,5 @@
+-DCONFIG_ZMK_BEHAVIOR_METADATA=y
+-DCONFIG_ZMK_BEHAVIOR_LOCAL_IDS=y
+-DCONFIG_ZMK_KEYMAP_LAYER_REORDERING=y
+-DCONFIG_ZMK_KEYMAP_SETTINGS_STORAGE=y
+-DCONFIG_SETTINGS=y

app/tests/studio/remove-layer/basic/keycode_events.snapshot

@@ -0,0 +1,7 @@
+remove_layer: Removed layer at index 1
+layer_changed: layer 1 state 1 locked 1
+pressed: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00
+released: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00
+layer_changed: layer 2 state 1 locked 1
+pressed: usage_page 0x07 keycode 0x06 implicit_mods 0x00 explicit_mods 0x00
+released: usage_page 0x07 keycode 0x06 implicit_mods 0x00 explicit_mods 0x00

app/tests/studio/remove-layer/basic/native_sim.conf

@@ -0,0 +1 @@
+CONFIG_ZMK_TEST_BEHAVIORS=y

app/tests/studio/remove-layer/basic/native_sim.keymap

@@ -0,0 +1,25 @@
+#include <dt-bindings/zmk/keys.h>
+#include <behaviors.dtsi>
+#include <dt-bindings/zmk/kscan_mock.h>
+#include "../behavior_keymap.dtsi"
+
+// Test removing layer 1
+&kscan {
+    events = <
+    // remove layer 1
+    ZMK_MOCK_PRESS(1,0,10)
+    ZMK_MOCK_RELEASE(1,0,10)
+    // toggle layer 1 on
+    ZMK_MOCK_PRESS(0,1,10)
+    ZMK_MOCK_RELEASE(0,1,10)
+    // press position 0,0 - should output A (layer 0) because layer 1 was removed
+    ZMK_MOCK_PRESS(0,0,10)
+    ZMK_MOCK_RELEASE(0,0,10)
+    // toggle layer 2 on
+    ZMK_MOCK_PRESS(1,1,10)
+    ZMK_MOCK_RELEASE(1,1,10)
+    // press position 0,0 - should output C (layer 2)
+    ZMK_MOCK_PRESS(0,0,10)
+    ZMK_MOCK_RELEASE(0,0,10)
+    >;
+};

app/tests/studio/remove-layer/behavior_keymap.dtsi

@@ -0,0 +1,34 @@
+#include <dt-bindings/zmk/keys.h>
+#include <behaviors.dtsi>
+#include <dt-bindings/zmk/kscan_mock.h>
+
+/ {
+    behaviors {
+        remove_layer_behavior: remove_layer_behavior {
+            compatible = "zmk,behavior-remove-layer";
+            #binding-cells = <1>;
+        };
+    };
+
+    keymap {
+        compatible = "zmk,keymap";
+
+        default_layer {
+            bindings = <
+                &kp A &tog 1
+                &remove_layer_behavior 1 &tog 2>;
+        };
+
+        layer_1 {
+            bindings = <
+                &kp B &tog 1
+                &remove_layer_behavior 0 &trans>;
+        };
+
+        layer_2 {
+            bindings = <
+                &kp C &trans
+                &none &trans>;
+        };
+    };
+};

app/tests/studio/remove-layer/remove-default-layer/events.patterns

@@ -0,0 +1,5 @@
+s/.*layer_changed/layer_changed/p
+s/.*hid_listener_keycode_//p
+s/.*on_remove_layer_binding_pressed/remove_layer/p
+s/.*tog_keymap_binding_pressed/tog_pressed/p
+

app/tests/studio/remove-layer/remove-default-layer/extra-cmake-args

@@ -0,0 +1,5 @@
+-DCONFIG_ZMK_BEHAVIOR_METADATA=y
+-DCONFIG_ZMK_BEHAVIOR_LOCAL_IDS=y
+-DCONFIG_ZMK_KEYMAP_LAYER_REORDERING=y
+-DCONFIG_ZMK_KEYMAP_SETTINGS_STORAGE=y
+-DCONFIG_SETTINGS=y

app/tests/studio/remove-layer/remove-default-layer/keycode_events.snapshot

@@ -0,0 +1,8 @@
+tog_pressed: position 1 layer 1
+layer_changed: layer 1 state 1 locked 1
+remove_layer: Removed layer at index 0
+pressed: usage_page 0x07 keycode 0x05 implicit_mods 0x00 explicit_mods 0x00
+released: usage_page 0x07 keycode 0x05 implicit_mods 0x00 explicit_mods 0x00
+tog_pressed: position 1 layer 1
+pressed: usage_page 0x07 keycode 0x05 implicit_mods 0x00 explicit_mods 0x00
+released: usage_page 0x07 keycode 0x05 implicit_mods 0x00 explicit_mods 0x00

app/tests/studio/remove-layer/remove-default-layer/native_sim.conf

@@ -0,0 +1 @@
+CONFIG_ZMK_TEST_BEHAVIORS=y

app/tests/studio/remove-layer/remove-default-layer/native_sim.keymap

@@ -0,0 +1,26 @@
+#include <dt-bindings/zmk/keys.h>
+#include <behaviors.dtsi>
+#include <dt-bindings/zmk/kscan_mock.h>
+#include "../behavior_keymap.dtsi"
+
+// Test removing layer 0: layer 1 becomes bottom layer
+&kscan {
+    events = <
+    // toggle layer 1 on
+    ZMK_MOCK_PRESS(0,1,10)
+    ZMK_MOCK_RELEASE(0,1,10)
+    // remove layer 0
+    ZMK_MOCK_PRESS(1,0,10)
+    ZMK_MOCK_RELEASE(1,0,10)
+    // press position 0,0 - should output B (layer 1)
+    ZMK_MOCK_PRESS(0,0,10)
+    ZMK_MOCK_RELEASE(0,0,10)
+    // try to toggle layer 1 off
+    ZMK_MOCK_PRESS(0,1,10)
+    ZMK_MOCK_RELEASE(0,1,10)
+    // press position 0,0 - should output B
+    // (layer 1 is now the bottom layer, so shouldn't be disabled)
+    ZMK_MOCK_PRESS(0,0,10)
+    ZMK_MOCK_RELEASE(0,0,10)
+    >;
+};

app/tests/studio/remove-layer/remove-default-layer/pending

@@ -0,0 +1,2 @@
+This test fails because the keymap function handling position state changes doesn't work correctly when the default layer is removed.
+The iteration loop's end condition is incorrect.