diff --git a/tests/vm_bitfont.c b/tests/vm_bitfont.c
new file mode 100644
index 0000000..bf3632b
--- /dev/null
+++ b/tests/vm_bitfont.c
@@ -0,0 +1,61 @@
+/*
+ * vm_bitfont.c
+ */
+
+#include <criterion/criterion.h>
+
+#include "vm_bitfont.h"
+
+static vm_bitfont *font;
+
+static void
+setup()
+{
+    vm_screen *screen;
+
+    screen = vm_screen_create();
+    font = vm_bitfont_create(screen, "apple2-system", 7, 8, 0x7F);
+}
+
+static void
+teardown()
+{
+    vm_bitfont_free(font);
+}
+
+TestSuite(vm_bitfont, .init = setup, .fini = teardown);
+
+Test(vm_bitfont, create)
+{
+    cr_assert_neq(font, NULL);
+
+    cr_assert_eq(font->width, 7);
+    cr_assert_eq(font->height, 8);
+    cr_assert_eq(font->cmask, 0x7F);
+
+    // This should be NULL because we have no screen
+    cr_assert_eq(font->texture, NULL);
+}
+
+Test(vm_bitfont, offset)
+{
+    char ch = 'p';
+    int x = 0;
+    int y = 0;
+
+    vm_bitfont_offset(font, ch, &x, &y);
+    
+    cr_assert_eq(x, (ch & 0x0f) * font->width);
+    cr_assert_eq(y, (ch >> 4) * font->height);
+}
+
+/*
+ * A note: I omitted a test for vm_bitfont_render(), as this function is
+ * a) reliant on vm_bitfont_offset for the right glyph to render, and b)
+ * is otherwise reliant on our graphics library to properly render the
+ * character. As we run our tests in a headless mode, we are unable to
+ * automate that specific kind of test.
+ */
+Test(vm_bitfont, render)
+{
+}
diff --git a/tests/vm_screen.c b/tests/vm_screen.c
index 237d3d8..a61279c 100644
--- a/tests/vm_screen.c
+++ b/tests/vm_screen.c
@@ -1,11 +1,34 @@
+/*
+ * vm_screen.c
+ *
+ * Generally speaking the tests here are very incomplete; this is partly
+ * because a lot of the code in vm_screen depends on a third-party
+ * graphics library, but I think we can do a better job of decoupling
+ * some concepts (like screen areas) from the graphics library, such
+ * that we can make the code that uses those testable.
+ */
+
 #include <criterion/criterion.h>
 
 #include "vm_screen.h"
 
-Test(vm_screen, create) {
-    vm_screen *screen;
+static vm_screen *screen;
 
+static void
+setup()
+{
     screen = vm_screen_create();
+}
+
+static void
+teardown()
+{
+    vm_screen_free(screen);
+}
+
+TestSuite(vm_screen, .init = setup, .fini = teardown);
+
+Test(vm_screen, create) {
     cr_assert_neq(screen, NULL);
 
     cr_assert_eq(screen->window, NULL);
@@ -16,6 +39,20 @@ Test(vm_screen, create) {
     cr_assert_eq(screen->rect.h, 0);
     cr_assert_eq(screen->xcoords, 0);
     cr_assert_eq(screen->ycoords, 0);
-
-    vm_screen_free(screen);
+}
+
+Test(vm_screen, xcoords)
+{
+    screen->xcoords = 123;
+    cr_assert_eq(screen->xcoords, 123);
+    screen->xcoords = 234;
+    cr_assert_eq(screen->xcoords, 234);
+}
+
+Test(vm_screen, ycoords)
+{
+    screen->ycoords = 123;
+    cr_assert_eq(screen->ycoords, 123);
+    screen->ycoords = 234;
+    cr_assert_eq(screen->ycoords, 234);
 }