Make string global in test to avoid sanitizer errors

Author: joto

test/t/io/test_reader_with_mock_decompression.cpp

@@ -76,9 +76,9 @@ class MockDecompressor final : public osmium::io::Decompressor {
 
 }; // class MockDecompressor
 
-TEST_CASE("Test Reader using MockDecompressor") {
+std::string fail_in;
 
-    std::string fail_in;
+TEST_CASE("Test Reader using MockDecompressor") {
 
     osmium::io::CompressionFactory::instance().register_compression(osmium::io::file_compression::gzip,
         [](int /*unused*/, osmium::io::fsync /*unused*/) { return nullptr; },

test/t/io/test_writer_with_mock_compression.cpp

@@ -46,9 +46,9 @@ class MockCompressor final : public osmium::io::Compressor {
 
 }; // class MockCompressor
 
-TEST_CASE("Write with mock compressor") {
+std::string fail_in;
 
-    std::string fail_in;
+TEST_CASE("Write with mock compressor") {
 
     osmium::io::CompressionFactory::instance().register_compression(osmium::io::file_compression::gzip,
         [&](int /*unused*/, osmium::io::fsync /*unused*/) { return new MockCompressor(fail_in); },