diff --git a/tests/suites/test_suite_entropy.data b/tests/suites/test_suite_entropy.data
index abf36c0..b2d20b4 100644
--- a/tests/suites/test_suite_entropy.data
+++ b/tests/suites/test_suite_entropy.data
@@ -43,6 +43,24 @@
 Entropy threshold: 1024 never reached
 entropy_threshold:1024:1:MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
 
+Entropy calls: no strong
+entropy_calls:MBEDTLS_ENTROPY_SOURCE_WEAK:MBEDTLS_ENTROPY_SOURCE_WEAK:1:MBEDTLS_ENTROPY_BLOCK_SIZE:MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE
+
+Entropy calls: 1 strong, 1*BLOCK_SIZE
+entropy_calls:MBEDTLS_ENTROPY_SOURCE_STRONG:MBEDTLS_ENTROPY_SOURCE_WEAK:1:MBEDTLS_ENTROPY_BLOCK_SIZE:1
+
+Entropy calls: 1 strong, 2*(BLOCK_SIZE/2)
+entropy_calls:MBEDTLS_ENTROPY_SOURCE_STRONG:MBEDTLS_ENTROPY_SOURCE_WEAK:1:(MBEDTLS_ENTROPY_BLOCK_SIZE+1)/2:2
+
+Entropy calls: 1 strong, BLOCK_SIZE*1
+entropy_calls:MBEDTLS_ENTROPY_SOURCE_STRONG:MBEDTLS_ENTROPY_SOURCE_WEAK:1:1:MBEDTLS_ENTROPY_BLOCK_SIZE
+
+Entropy calls: 1 strong, 2*BLOCK_SIZE to reach threshold
+entropy_calls:MBEDTLS_ENTROPY_SOURCE_STRONG:MBEDTLS_ENTROPY_SOURCE_WEAK:MBEDTLS_ENTROPY_BLOCK_SIZE+1:MBEDTLS_ENTROPY_BLOCK_SIZE:2
+
+Entropy calls: 2 strong, BLOCK_SIZE/2 each
+entropy_calls:MBEDTLS_ENTROPY_SOURCE_STRONG:MBEDTLS_ENTROPY_SOURCE_WEAK:(MBEDTLS_ENTROPY_BLOCK_SIZE+1)/2:(MBEDTLS_ENTROPY_BLOCK_SIZE+1)/2:2
+
 Check NV seed standard IO
 entropy_nv_seed_std_io:
 
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(  )
 {