Add unit test for font.c

src/CMakeLists.txt

@@ -10,6 +10,7 @@ add_library(src_lib STATIC
   cali.c
   dri.c
   filecheck.c
+  font.c
   gameresource.c
   hankaku.c
   mmap.c
@@ -72,7 +73,6 @@ target_sources(xsystem35 PRIVATE
   ecopy.c
   effect.c
   event.c
-  font.c
   hacks.c
   gfx_draw.c
   gfx_image.c
@@ -137,16 +137,17 @@ if (ENABLE_DEBUGGER)
 endif()
 
 if (WIN32)
+  target_sources(src_lib PRIVATE win/resources.c)
   target_sources(xsystem35 PRIVATE
-    win/dialog.c win/resources.rc win/resources.c win/menubar.c win/console.c)
+    win/dialog.c win/resources.rc win/menubar.c win/console.c)
 endif()
 
 if (NOT HAVE_LIBINTL)
   target_sources(xsystem35 PRIVATE nls.c)
 endif()
 
-target_link_libraries(src_lib PRIVATE sdl2 zlib)
-target_link_libraries(xsystem35 PRIVATE m zlib sdl2 freetype2)
+target_link_libraries(src_lib PRIVATE sdl2 freetype2 zlib)
+target_link_libraries(xsystem35 PRIVATE m zlib sdl2)
 if (TARGET sdl2_mixer)
   target_link_libraries(xsystem35 PRIVATE sdl2_mixer)
 endif()
@@ -201,12 +202,15 @@ else()  # non-emscripten, non-android
 
   add_executable(src_tests
     src_tests.c
+    font_test.c
     gameresource_test.c
     hankaku_test.c
     qnt_test.c
     variable_test.c
     )
   target_compile_options(src_tests PRIVATE -Wno-pointer-sign -Wall)
+  target_compile_definitions(src_tests PRIVATE
+      TEST_FONT_DIR="${PROJECT_SOURCE_DIR}/fonts")
   target_link_libraries(src_tests PRIVATE src_lib sdl2)
   add_test(NAME src_tests COMMAND src_tests)
   file(COPY testdata DESTINATION ${CMAKE_CURRENT_BINARY_DIR})

src/font_test.c

@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2026 <KichikuouChrome@gmail.com>
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "font.h"
+#include "unittest.h"
+
+#include <SDL.h>
+
+static const FontType font_types[] = {FONT_GOTHIC, FONT_MINCHO};
+#define NTYPES ((int)(sizeof(font_types) / sizeof(font_types[0])))
+
+static const int sizes[] = {8, 16, 24, 32};
+#define NSIZES ((int)(sizeof(sizes) / sizeof(sizes[0])))
+
+static const char *texts[] = {
+	"Hello, world!",
+	" ",
+	"iWiW",
+	"\xe9\xad\x94\xe7\x89\xa9\xe3\x81\xae\xe6\xa3\xae",  // 魔物の森
+	"\xe3\x81\x82\xe3\x81\x84\xe3\x81\x86"               // あいう
+	"\xe3\x82\xa2\xe3\x82\xa4\xe3\x82\xa6",              // アイウ
+};
+#define NTEXTS ((int)(sizeof(texts) / sizeof(texts[0])))
+
+static const SDL_Color white = {255, 255, 255, 255};
+
+static int measure_w(FontSpec f, const char *s) {
+	int w;
+	font_measure_text(f, s, -1, &w, NULL);
+	return w;
+}
+
+static int measure_h(FontSpec f) {
+	int h;
+	font_measure_text(f, "", -1, NULL, &h);
+	return h;
+}
+
+static void invariants_test(void) {
+	for (int ti = 0; ti < NTYPES; ti++) {
+		for (int si = 0; si < NSIZES; si++) {
+			FontSpec f = {font_types[ti], FONT_WEIGHT_NORMAL, sizes[si]};
+			for (int i = 0; i < NTEXTS; i++) {
+				const char *text = texts[i];
+				for (int aa = 0; aa < 2; aa++) {
+					SDL_Surface *s = font_render_text(f, text, white, aa);
+					ASSERT_TRUE(s);
+					// gfx_drawString() blits the surface using the measured
+					// width, so the two must agree.
+					ASSERT_EQUAL(s->w, measure_w(f, text));
+					// microui lays out text rows by the measured height,
+					// so the surface must be exactly that tall.
+					ASSERT_EQUAL(s->h, measure_h(f));
+					// The antialiased surface goes to gfx_drawAntiAlias_8bpp(),
+					// which reads a 32-bit alpha channel. The other one is
+					// blitted onto the indexed screen surface as is.
+					ASSERT_EQUAL(s->format->BitsPerPixel, aa ? 32 : 8);
+					SDL_FreeSurface(s);
+				}
+			}
+			// gfx_drawString() draws text by the top of the character cell,
+			// shifting the surface up by the overhang. The result must cover
+			// the whole cell.
+			ASSERT_TRUE(font_cell_overhang(f) >= 0);
+			ASSERT_TRUE(measure_h(f) - font_cell_overhang(f) >= f.size);
+
+			// microui positions the text cursor by measuring a prefix of the
+			// string, so that must equal measuring a truncated copy.
+			const char *text = texts[0];
+			for (int len = 0; text[len]; len++) {
+				char buf[64];
+				int w;
+				font_measure_text(f, text, len, &w, NULL);
+				memcpy(buf, text, len);
+				buf[len] = '\0';
+				ASSERT_EQUAL(w, measure_w(f, buf));
+			}
+		}
+	}
+}
+
+void font_test(void) {
+	font_init();
+	font_set_name_and_index(FONT_GOTHIC, TEST_FONT_DIR "/MTLc3m.ttf", 0);
+	font_set_name_and_index(FONT_MINCHO, TEST_FONT_DIR "/mincho.ttf", 0);
+
+	invariants_test();
+}

src/src_tests.c

@@ -20,6 +20,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+void font_test(void);
 void gameresource_test(void);
 void hankaku_test(void);
 void qnt_test(void);
@@ -41,6 +42,7 @@ void sys_message(int level, char *format, ...) {
 }
 
 int main() {
+	font_test();
 	gameresource_test();
 	variable_test();
 	hankaku_test();