[liba] stdint size checks

liba/include/stdint.h

@@ -7,6 +7,7 @@ typedef unsigned long uint32_t;
 typedef unsigned long long uint64_t;
 
 typedef signed char int8_t;
+typedef signed int int16_t;
 typedef signed long int32_t;
 typedef signed long long int64_t;
 

liba/test/stdint.c

@@ -2,11 +2,28 @@
 #include <stdint.h>
 #include <assert.h>
 
-QUIZ_CASE(liba_stdint) {
-  int8_t i = -1;
-  int j = -1;
-  assert(i == -1);
-  assert(i == j);
+QUIZ_CASE(liba_stdint_size) {
+  assert(sizeof(uint8_t) == 1);
+  assert(sizeof(uint16_t) == 2);
+  assert(sizeof(uint32_t) == 4);
+  assert(sizeof(uint64_t) == 8);
+
   assert(sizeof(int8_t) == 1);
+  assert(sizeof(int16_t) == 2);
+  assert(sizeof(int32_t) == 4);
+  assert(sizeof(int64_t) == 8);
 }
 
+QUIZ_CASE(liba_stdint_signedness) {
+  int8_t i8 = -1;
+  assert(i8 == -1);
+
+  int16_t i16 = -1;
+  assert(i16 == -1);
+
+  int32_t i32 = -1;
+  assert(i32 == -1);
+
+  int64_t i64 = -1;
+  assert(i64 == -1);
+}