From 74705c811107ebc036bf519e973c8ebb0e3bb28d Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Tue, 4 Oct 2022 09:27:52 -0400
Subject: [PATCH] port error check test from fortran wrapper to c-library
 interface test

---
 .../c-library/test_library_properties.cpp     | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/unittest/c-library/test_library_properties.cpp b/unittest/c-library/test_library_properties.cpp
index 56c89a6c13..bbb363dfab 100644
--- a/unittest/c-library/test_library_properties.cpp
+++ b/unittest/c-library/test_library_properties.cpp
@@ -434,6 +434,33 @@ TEST_F(LibraryProperties, neighlist)
     }
 };
 
+TEST_F(LibraryProperties, has_error)
+{
+    // need errors to throw exceptions to be able to intercept them.
+    if (!lammps_config_has_exceptions()) GTEST_SKIP();
+
+    EXPECT_EQ(lammps_has_error(lmp), 0);
+
+    // trigger an error, but hide output
+    ::testing::internal::CaptureStdout();
+    lammps_command(lmp, "this_is_not_a_known_command");
+    ::testing::internal::GetCapturedStdout();
+
+    EXPECT_EQ(lammps_has_error(lmp), 1);
+
+    // retrieve error message
+    char errmsg[1024];
+    int err = lammps_get_last_error_message(lmp, errmsg, 1024);
+    EXPECT_EQ(err, 1);
+    EXPECT_THAT(errmsg, HasSubstr("ERROR: Unknown command: this_is_not_a_known_command"));
+
+    // retrieving the error message clear the error status
+    EXPECT_EQ(lammps_has_error(lmp), 0);
+    err = lammps_get_last_error_message(lmp, errmsg, 1024);
+    EXPECT_EQ(err, 0);
+    EXPECT_THAT(errmsg, StrEq(""));
+};
+
 class AtomProperties : public ::testing::Test {
 protected:
     void *lmp;