Unit test for zstd_compression.c

Add a unit test (and its infrastructure) for 'zstd_compress()'.

The test checks whether 'zstd_compress()' returns correct output in case
compression fails (compressed data is larger than uncompressed). To do that,
'ZSTD_compressCCtx()' is mocked to always return 'ZSTD_error_dstSize_tooSmall'.

Also, an 'ifndef' is added around 'PG_MODULE_MAGIC' in zstd_compression.c

gpcontrib/zstd/Makefile

@@ -20,11 +20,13 @@ endif
 # Install into cdb_init.d, so that the catalog changes performed by initdb,
 # and the compressor is available in all databases.
 .PHONY: install-data
+
 install-data:
 	$(INSTALL_DATA) zstd_compression.sql '$(DESTDIR)$(datadir)/cdb_init.d/zstd_compression.sql'
 
 install: install-data
 
+
 .PHONY: uninstall-data
 
 uninstall-data:
@@ -32,3 +34,12 @@ uninstall-data:
 
 uninstall: uninstall-data
 
+
+.PHONY: unittest-check unittest-clean
+
+unittest-check:
+	$(MAKE) -C test check
+
+unittest-clean:
+	$(MAKE) -C test clean
+

gpcontrib/zstd/test/Makefile

+subdir=gpcontrib/zstd/test
+top_builddir=../../..
+
+include $(top_builddir)/src/Makefile.global
+
+TARGETS= zstd_compression
+
+include $(top_builddir)/src/backend/mock.mk

gpcontrib/zstd/test/mock/zstd_mock.c

+/* mock functions for zstd.h */
+size_t
+ZSTD_compressCCtx(ZSTD_CCtx * ctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, int compressionLevel)
+{
+	return (size_t) -ZSTD_error_dstSize_tooSmall;
+}

gpcontrib/zstd/test/zstd_compression_test.c

+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include "cmockery.h"
+
+#define UNIT_TESTING
+
+/* Include unit under test */
+#include "../zstd_compression.c"
+
+/* Include mock functions for zstd.h */
+#include "mock/zstd_mock.c"
+
+
+/*
+ * Test compression failure when compressed data is larger than uncompressed
+ */
+void
+test_uncompressed_sz_equals_compressed_sz(void **state)
+{
+	int32		uncompressed_size = 42;
+	int32		compressed_size = 0;
+
+	DirectFunctionCall6(
+						zstd_compress,
+						PointerGetDatum(NULL),
+						Int32GetDatum(uncompressed_size),
+						PointerGetDatum(NULL),
+						Int32GetDatum(uncompressed_size),
+						PointerGetDatum(&compressed_size),
+						PointerGetDatum(NULL)
+		);
+
+	assert_int_equal(compressed_size, uncompressed_size);
+}
+
+int
+main(int argc, char *argv[])
+{
+	cmockery_parse_arguments(argc, argv);
+
+	const		UnitTest tests[] = {
+		unit_test(test_uncompressed_sz_equals_compressed_sz),
+	};
+
+	MemoryContextInit();
+
+	return run_tests(tests);
+}

gpcontrib/zstd/zstd_compression.c

@@ -18,6 +18,10 @@
 #include <zstd.h>
 #include <zstd_errors.h>
 
+#ifndef PG_MODULE_MAGIC
+PG_MODULE_MAGIC;
+#endif
+
 Datum zstd_constructor(PG_FUNCTION_ARGS);
 Datum zstd_destructor(PG_FUNCTION_ARGS);
 Datum zstd_compress(PG_FUNCTION_ARGS);
@@ -30,7 +34,6 @@ PG_FUNCTION_INFO_V1(zstd_compress);
 PG_FUNCTION_INFO_V1(zstd_decompress);
 PG_FUNCTION_INFO_V1(zstd_validator);
 
-PG_MODULE_MAGIC;
 
 /* Internal state for zstd */
 typedef struct zstd_state

src/backend/catalog/pg_compression.c

@@ -81,7 +81,7 @@ comptype_to_name(char *comptype)
 	len = strlen(comptype);
 	dct = asc_tolower(comptype, len);
 	len = strlen(dct);
-	
+
 	memcpy(&(NameStr(compname)), dct, len);
 	NameStr(compname)[len] = '\0';
 	pfree(dct);