Add tests to ensure that we gather as much entropy as expected
There were tests to ensure that each entropy source reaches its
threshold, but no test that covers the total amount of entropy. Add
test cases with a known set of entropy sources and make sure that we
always gather at least MBEDTLS_ENTROPY_BLOCK_SIZE bytes from a strong
source.
diff --git a/tests/suites/test_suite_entropy.function b/tests/suites/test_suite_entropy.function
index a125f62..d1d88c5 100644
--- a/tests/suites/test_suite_entropy.function
+++ b/tests/suites/test_suite_entropy.function
@@ -286,6 +286,49 @@
}
/* END_CASE */
+/* BEGIN_CASE */
+void entropy_calls( int strength1, int strength2,
+ int threshold, int chunk_size,
+ int result )
+{
+ /*
+ * if result >= 0: result = expected number of calls to source 1
+ * if result < 0: result = expected return code from mbedtls_entropy_func()
+ */
+
+ mbedtls_entropy_context ctx;
+ entropy_dummy_context dummy1 = {DUMMY_CONSTANT_LENGTH, chunk_size, 0};
+ entropy_dummy_context dummy2 = {DUMMY_CONSTANT_LENGTH, chunk_size, 0};
+ unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 };
+ int ret;
+
+ mbedtls_entropy_init( &ctx );
+ entropy_clear_sources( &ctx );
+
+ TEST_ASSERT( mbedtls_entropy_add_source( &ctx, entropy_dummy_source,
+ &dummy1, threshold,
+ strength1 ) == 0 );
+ TEST_ASSERT( mbedtls_entropy_add_source( &ctx, entropy_dummy_source,
+ &dummy2, threshold,
+ strength2 ) == 0 );
+
+ ret = mbedtls_entropy_func( &ctx, buf, sizeof( buf ) );
+
+ if( result >= 0 )
+ {
+ TEST_ASSERT( ret == 0 );
+ TEST_ASSERT( dummy1.calls == (size_t) result );
+ }
+ else
+ {
+ TEST_ASSERT( ret == result );
+ }
+
+exit:
+ mbedtls_entropy_free( &ctx );
+}
+/* END_CASE */
+
/* BEGIN_CASE depends_on:MBEDTLS_ENTROPY_NV_SEED:MBEDTLS_FS_IO */
void nv_seed_file_create( )
{