Exercise string parsing in the test framework

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

tests/suites/test_suite_platform_printf.function

@@ -4,6 +4,13 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+
+#define NEWLINE_CHAR '\n'
+#define SPACE_CHAR ' '
+#define DOUBLE_QUOTE_CHAR '"'
+#define COLON_CHAR ':'
+#define BACKSLASH_CHAR '\\'
+#define LOWERCASE_N_CHAR 'n'
 /* END_HEADER */
 
 /* BEGIN_CASE */
@@ -23,3 +30,21 @@ exit:
     mbedtls_free(output);
 }
 /* END_CASE */
+
+/* BEGIN_CASE */
+void printf_char2(char *format, int arg1, int arg2, char *result)
+{
+    char *output = NULL;
+    const size_t n = strlen(result);
+
+    /* Nominal case: buffer just large enough */
+    ASSERT_ALLOC(output, n + 1);
+    TEST_EQUAL(n, mbedtls_snprintf(output, n + 1, format, arg1, arg2));
+    ASSERT_COMPARE(result, n + 1, output, n + 1);
+    mbedtls_free(output);
+    output = NULL;
+
+exit:
+    mbedtls_free(output);
+}
+/* END_CASE */