screen: Abstract out oled functions

diff --git a/src/bootloader/startup.c b/src/bootloader/startup.c
index ea960b2..5295977 100644
--- a/src/bootloader/startup.c
+++ b/src/bootloader/startup.c
@@ -22,6 +22,7 @@
 #include <rust/rust.h>
 #include <screen.h>
 #include <string.h>
+#include <ui/oled/oled.h>
 #include <usb/class/hid/hww/hid_hww.h>
 #include <usb/usb_processing.h>
 
@@ -82,7 +83,7 @@ int main(void)
     bootloader_init();
     platform_init();
     __stack_chk_guard = rand_sync_read32(&RAND_0);
-    screen_init();
+    screen_init(oled_set_pixel, oled_mirror, oled_clear_buffer);
 #if defined(BOOTLOADER_DEVDEVICE) || PLATFORM_BITBOX02PLUS == 1
     qtouch_init();
 #endif
diff --git a/src/factorysetup.c b/src/factorysetup.c
index 8f99de6..2af7fed 100644
--- a/src/factorysetup.c
+++ b/src/factorysetup.c
@@ -33,6 +33,7 @@
 #include "usb/usb_processing.h"
 #include "utils_ringbuffer.h"
 #include <secp256k1.h>
+#include <ui/oled/oled.h>
 
 #include <wally_crypto.h>
 
@@ -581,7 +582,7 @@ int main(void)
     system_init();
     platform_init();
     __stack_chk_guard = common_stack_chk_guard();
-    screen_init();
+    screen_init(oled_set_pixel, oled_mirror, oled_clear_buffer);
     screen_splash();
     common_main();
 
diff --git a/src/firmware.c b/src/firmware.c
index ff0813d..6af86f8 100644
--- a/src/firmware.c
+++ b/src/firmware.c
@@ -27,6 +27,7 @@
 #include "usb/usb_processing.h"
 #include <hww.h>
 #include <memory/memory_spi.h>
+#include <ui/oled/oled.h>
 
 #if APP_U2F == 1
 #include <u2f.h>
@@ -40,7 +41,7 @@ int main(void)
     system_init();
     platform_init();
     __stack_chk_guard = common_stack_chk_guard();
-    screen_init();
+    screen_init(oled_set_pixel, oled_mirror, oled_clear_buffer);
     screen_splash();
     qtouch_init();
     common_main();
diff --git a/src/reset.c b/src/reset.c
index 4b222e2..f860fd4 100644
--- a/src/reset.c
+++ b/src/reset.c
@@ -22,6 +22,7 @@
 #include "memory/smarteeprom.h"
 #include "system.h"
 #include "uart.h"
+#include <screen.h>
 
 #ifndef TESTING
 #include "securechip/securechip.h"
@@ -40,7 +41,7 @@ static void _show_reset_label(bool status)
 {
     const char* msg = "Device reset";
     component_t* comp = status_create(msg, status, NULL, NULL);
-    UG_ClearBuffer();
+    screen_clear();
     comp->f->render(comp);
     UG_SendBuffer();
     comp->f->cleanup(comp);
diff --git a/src/screen.c b/src/screen.c
index 5ca2a8b..f0fbecd 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -14,7 +14,6 @@
 
 #include "screen.h"
 
-#include <hal_delay.h>
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stdint.h>
@@ -24,9 +23,16 @@
 #include <ui/oled/oled.h>
 #include <ui/ugui/ugui.h>
 #include <util.h>
+#include <utils_assert.h>
+
+#ifndef TESTING
+#include <hal_delay.h>
+#endif
 
 static UG_GUI guioled; // Global GUI structure for OLED screen
 static bool screen_upside_down = false;
+static void (*_mirror_fn)(bool);
+static void (*_clear_fn)(void);
 
 UG_COLOR screen_front_color = C_WHITE;
 UG_COLOR screen_back_color = C_BLACK;
@@ -39,11 +45,13 @@ void screen_print_debug(const char* message, int duration)
 {
     char print[100];
     snprintf(print, sizeof(print), "%s", message);
-    UG_ClearBuffer();
+    screen_clear();
     UG_FontSelect(&font_font_a_9X9);
     UG_PutString(0, 0, print, false);
     UG_SendBuffer();
+#ifndef TESTING
     if (duration > 0) delay_ms(duration);
+#endif
 }
 
 void screen_sprintf_debug(int duration, const char* fmt, ...)
@@ -71,7 +79,7 @@ void screen_print_debug_hex(const uint8_t* bytes, size_t len, int duration)
 // Careful, this function is used in both the bootloader and the firmware.
 void screen_splash(void)
 {
-    UG_ClearBuffer();
+    screen_clear();
 
     int height = IMAGE_DEFAULT_ARROW_HEIGHT;
     int x = 0;
@@ -80,7 +88,7 @@ void screen_splash(void)
     image_arrow(SCREEN_WIDTH - x - 2, y, height, ARROW_LEFT);
 
     UG_SendBuffer();
-    UG_ClearBuffer();
+    screen_clear();
 }
 
 void screen_rotate(void)
@@ -88,7 +96,8 @@ void screen_rotate(void)
     screen_upside_down = !screen_upside_down;
     top_slider = 1 - top_slider;
     bottom_slider = 1 - bottom_slider;
-    oled_mirror(screen_upside_down);
+    ASSERT(_mirror_fn);
+    _mirror_fn(screen_upside_down);
 }
 
 bool screen_is_upside_down(void)
@@ -96,12 +105,18 @@ bool screen_is_upside_down(void)
     return screen_upside_down;
 }
 
-void screen_init(void)
+void screen_init(
+    void (*pixel_fn)(UG_S16, UG_S16, UG_COLOR),
+    void (*mirror_fn)(bool),
+    void (*clear_fn)(void))
+{
+    _mirror_fn = mirror_fn;
+    _clear_fn = clear_fn;
+    UG_Init(&guioled, pixel_fn, &font_font_a_11X10, SCREEN_WIDTH, SCREEN_HEIGHT);
+}
+
+void screen_clear(void)
 {
-    UG_Init(
-        &guioled,
-        (void (*)(UG_S16, UG_S16, UG_COLOR))oled_set_pixel,
-        &font_font_a_11X10,
-        SCREEN_WIDTH,
-        SCREEN_HEIGHT);
+    ASSERT(_clear_fn);
+    _clear_fn();
 }
diff --git a/src/screen.h b/src/screen.h
index 836e160..a2f4388 100644
--- a/src/screen.h
+++ b/src/screen.h
@@ -34,7 +34,10 @@ extern slider_location_t bottom_slider;
 #define SCREEN_WIDTH 128
 #define SCREEN_HEIGHT 64
 
-void screen_init(void);
+void screen_init(
+    void (*pixel_fn)(UG_S16, UG_S16, UG_COLOR),
+    void (*mirror_fn)(bool),
+    void (*clear_fn)(void));
 void screen_print_debug(const char* message, int duration);
 void screen_sprintf_debug(int duration, const char* fmt, ...) __attribute__((format(printf, 2, 0)));
 void screen_print_debug_hex(const uint8_t* bytes, size_t len, int duration);
@@ -45,4 +48,6 @@ void screen_rotate(void);
 
 bool screen_is_upside_down(void);
 
+void screen_clear(void);
+
 #endif
diff --git a/src/ui/graphics/lock_animation.c b/src/ui/graphics/lock_animation.c
index fdadcd1..e7a1b96 100644
--- a/src/ui/graphics/lock_animation.c
+++ b/src/ui/graphics/lock_animation.c
@@ -165,7 +165,7 @@ static void _animation_timer_cb(const struct timer_task* const timer_task)
     }
 
     /* Draw the frame. */
-    UG_ClearBuffer();
+    screen_clear();
     position_t pos = {
         .left = (SCREEN_WIDTH - LOCK_ANIMATION_FRAME_WIDTH) / 2,
         .top = (SCREEN_HEIGHT - LOCK_ANIMATION_FRAME_HEIGHT) / 2};
diff --git a/src/ui/oled/oled.c b/src/ui/oled/oled.c
index 9fbf817..713547e 100644
--- a/src/ui/oled/oled.c
+++ b/src/ui/oled/oled.c
@@ -84,7 +84,7 @@ static volatile bool _enabled = false;
 
 struct bb02_display {
     void (*configure)(uint8_t*);
-    void (*set_pixel)(uint16_t x, uint16_t y, uint8_t c);
+    void (*set_pixel)(int16_t x, int16_t y, uint8_t c);
     void (*update)(void);
     void (*off)(void);
     void (*mirror)(bool);
@@ -146,7 +146,7 @@ void oled_mirror(bool mirror)
     bb02_display.mirror(mirror);
 }
 
-void oled_set_pixel(uint16_t x, uint16_t y, uint8_t c)
+void oled_set_pixel(int16_t x, int16_t y, uint8_t c)
 {
     bb02_display.set_pixel(x, y, c);
     _frame_buffer_updated = true;
diff --git a/src/ui/oled/oled.h b/src/ui/oled/oled.h
index 43217c1..c73faed 100644
--- a/src/ui/oled/oled.h
+++ b/src/ui/oled/oled.h
@@ -94,7 +94,7 @@ void oled_off(void);
  * Set a screen pixel. This fills the frame buffer
  * prior to it being sent to the screen by oled_send_buffer().
  */
-void oled_set_pixel(uint16_t x, uint16_t y, uint8_t c);
+void oled_set_pixel(int16_t x, int16_t y, uint8_t c);
 
 /**
  * Set brightness (0x00..0xff).
diff --git a/src/ui/oled/sh1107.c b/src/ui/oled/sh1107.c
index de2da75..544e672 100644
--- a/src/ui/oled/sh1107.c
+++ b/src/ui/oled/sh1107.c
@@ -97,11 +97,11 @@ void sh1107_configure(uint8_t* buf)
 }
 
 /* pixels can be accessed via buf[y*16+x/8] >> x%8 */
-void sh1107_set_pixel(uint16_t x, uint16_t y, uint8_t c)
+void sh1107_set_pixel(int16_t x, int16_t y, uint8_t c)
 {
     uint32_t p;
-    if (x > 127) return;
-    if (y > 63) return;
+    if (x < 0 || x > 127) return;
+    if (y < 0 || y > 63) return;
     p = y * 16;
     p += x / 8;
     if (c) {
diff --git a/src/ui/oled/sh1107.h b/src/ui/oled/sh1107.h
index df76f32..f6f0c42 100644
--- a/src/ui/oled/sh1107.h
+++ b/src/ui/oled/sh1107.h
@@ -24,7 +24,7 @@
  */
 void sh1107_configure(uint8_t* buf);
 
-void sh1107_set_pixel(uint16_t x, uint16_t y, uint8_t c);
+void sh1107_set_pixel(int16_t x, int16_t y, uint8_t c);
 void sh1107_update(void);
 void sh1107_mirror(bool mirror);
 void sh1107_off(void);
diff --git a/src/ui/oled/ssd1312.c b/src/ui/oled/ssd1312.c
index ea51755..3d11f3e 100644
--- a/src/ui/oled/ssd1312.c
+++ b/src/ui/oled/ssd1312.c
@@ -102,11 +102,11 @@ void ssd1312_configure(uint8_t* buf)
     oled_writer_write_cmd(SSD1312_CMD_SET_DISPLAY_ON);
 }
 
-void ssd1312_set_pixel(uint16_t x, uint16_t y, uint8_t c)
+void ssd1312_set_pixel(int16_t x, int16_t y, uint8_t c)
 {
     uint32_t p;
-    if (x > 127) return;
-    if (y > 63) return;
+    if (x < 0 || x > 127) return;
+    if (y < 0 || y > 63) return;
     p = (y / 8) * 128;
     p += x;
     if (c) {
diff --git a/src/ui/oled/ssd1312.h b/src/ui/oled/ssd1312.h
index c5ae64a..2a0318e 100644
--- a/src/ui/oled/ssd1312.h
+++ b/src/ui/oled/ssd1312.h
@@ -23,7 +23,7 @@
  */
 void ssd1312_configure(uint8_t* buf);
 
-void ssd1312_set_pixel(uint16_t x, uint16_t y, uint8_t c);
+void ssd1312_set_pixel(int16_t x, int16_t y, uint8_t c);
 void ssd1312_update(void);
 void ssd1312_mirror(bool mirror);
 void ssd1312_off(void);
diff --git a/src/ui/screen_process.c b/src/ui/screen_process.c
index 74cec51..4320401 100644
--- a/src/ui/screen_process.c
+++ b/src/ui/screen_process.c
@@ -25,7 +25,7 @@ static uint8_t screen_frame_cnt = 0;
 
 void ui_screen_render_component(component_t* component)
 {
-    UG_ClearBuffer();
+    screen_clear();
     component->position.left = 0;
     component->position.top = 0;
     component->f->render(component);
@@ -91,12 +91,14 @@ void screen_process(void)
     component_t* component = screen_process_get_top_component();
     _screen_draw(component);
 
+#ifndef TESTING
     /*
      * If we have changed activity, the gestures
      * detection must start over.
      */
     bool screen_new = _screen_has_changed(component);
     gestures_detect(screen_new, component->emit_without_release);
+#endif
 
     ui_screen_stack_cleanup();
 }
diff --git a/test/unit-test/framework/mock_screen.c b/test/unit-test/framework/mock_screen.c
index 7e0e8fa..45d81ca 100644
--- a/test/unit-test/framework/mock_screen.c
+++ b/test/unit-test/framework/mock_screen.c
@@ -42,3 +42,5 @@ bool screen_is_upside_down(void)
 {
     return false;
 }
+
+void screen_clear(void) {}