diff --git a/src/tss2-tcti/tcti-mssim.c b/src/tss2-tcti/tcti-mssim.c
index a358452c6..5a83dbcbe 100644
--- a/src/tss2-tcti/tcti-mssim.c
+++ b/src/tss2-tcti/tcti-mssim.c
@@ -136,7 +136,7 @@ send_sim_session_end (
     TSS2_RC rc;
 
     rc = Tss2_MU_UINT32_Marshal (TPM_SESSION_END, buf, sizeof (buf), NULL);
-    if (rc == TSS2_RC_SUCCESS) {
+    if (rc != TSS2_RC_SUCCESS) {
         return rc;
     }
     return socket_xmit_buf (sock, buf, sizeof (buf));
diff --git a/test/unit/tcti-mssim.c b/test/unit/tcti-mssim.c
index c89149e7a..e32b4917a 100644
--- a/test/unit/tcti-mssim.c
+++ b/test/unit/tcti-mssim.c
@@ -336,6 +336,9 @@ tcti_socket_teardown (void **state)
 {
     TSS2_TCTI_CONTEXT *ctx = (TSS2_TCTI_CONTEXT*)*state;
 
+    will_return (__wrap_write, 4);
+    will_return (__wrap_write, 4);
+
     Tss2_Tcti_Finalize (ctx);
     free (ctx);
     return 0;
@@ -358,6 +361,7 @@ tcti_mssim_get_poll_handles_test (void **state)
     assert_int_equal (rc, TSS2_RC_SUCCESS);
     assert_int_equal (num_handles, 1);
     assert_int_equal (handles[0].fd, mssim_ctx->tpm_sock);
+
 }
 /*
  */