[yul-phaser] TestHelpers: Add TemporaryDirectory class

test/yulPhaser/TestHelpers.cpp

@@ -19,12 +19,18 @@
 
 #include <libyul/optimiser/Suite.h>
 
+#include <boost/filesystem.hpp>
+
 #include <regex>
+#include <iostream>
 
 using namespace std;
 using namespace solidity;
 using namespace solidity::yul;
 using namespace solidity::phaser;
+using namespace solidity::phaser::test;
+
+namespace fs = boost::filesystem;
 
 function<Mutation> phaser::test::wholeChromosomeReplacement(Chromosome _newChromosome)
 {
@@ -71,6 +77,40 @@ size_t phaser::test::countDifferences(Chromosome const& _chromosome1, Chromosome
 	return count + abs(static_cast<int>(_chromosome1.length() - _chromosome2.length()));
 }
 
+TemporaryDirectory::TemporaryDirectory(std::string const& _prefix):
+	m_path((fs::temp_directory_path() / fs::unique_path(_prefix + "%%%%-%%%%-%%%%-%%%%")).string())
+{
+	// Prefix should just be a file name and not contain anything that would make us step out of /tmp.
+	assert(fs::path(_prefix) == fs::path(_prefix).stem());
+
+	fs::create_directory(m_path);
+}
+
+TemporaryDirectory::~TemporaryDirectory()
+{
+	// A few paranoid sanity checks just to be extra sure we're not deleting someone's homework.
+	assert(m_path.find(fs::temp_directory_path().string()) == 0);
+	assert(fs::path(m_path) != fs::temp_directory_path());
+	assert(fs::path(m_path) != fs::path(m_path).root_path());
+	assert(!fs::path(m_path).empty());
+
+	boost::system::error_code errorCode;
+	uintmax_t numRemoved = fs::remove_all(m_path, errorCode);
+	if (errorCode.value() != boost::system::errc::success)
+	{
+		cerr << "Failed to completely remove temporary directory '" << m_path << "'. ";
+		cerr << "Only " << numRemoved << " files were actually removed." << endl;
+		cerr << "Reason: " << errorCode.message() << endl;
+	}
+}
+
+string TemporaryDirectory::memberPath(string const& _relativePath) const
+{
+	assert(fs::path(_relativePath).is_relative());
+
+	return (fs::path(m_path) / _relativePath).string();
+}
+
 string phaser::test::stripWhitespace(string const& input)
 {
 	regex whitespaceRegex("\\s+");

test/yulPhaser/TestHelpers.h

@@ -79,6 +79,31 @@ size_t countDifferences(Chromosome const& _chromosome1, Chromosome const& _chrom
 /// integers.
 std::map<std::string, size_t> enumerateOptmisationSteps();
 
+// FILESYSTEM UTILITIES
+
+/**
+ * An object that creates a unique temporary directory and automatically deletes it and its
+ * content upon being destroyed.
+ *
+ * The directory is guaranteed to be newly created and empty. Directory names are generated
+ * randomly. If a directory with the same name already exists (very unlikely but possible) the
+ * object won't reuse it and will fail with an exception instead.
+ */
+class TemporaryDirectory
+{
+public:
+	TemporaryDirectory(std::string const& _prefix = "yul-phaser-test-");
+	~TemporaryDirectory();
+
+	std::string const& path() const { return m_path; }
+
+	/// Converts a path relative to the directory held by the object into an absolute one.
+	std::string memberPath(std::string const& _relativePath) const;
+
+private:
+	std::string m_path;
+};
+
 // STRING UTILITIES
 
 /// Returns the input string with all the whitespace characters (spaces, line endings, etc.) removed.

test/yulPhaser/TestHelpersTest.cpp

@@ -19,14 +19,18 @@
 
 #include <libyul/optimiser/Suite.h>
 
+#include <boost/filesystem.hpp>
 #include <boost/test/unit_test.hpp>
 
+#include <fstream>
 #include <set>
 
 using namespace std;
 using namespace solidity::yul;
 using namespace boost::test_tools;
 
+namespace fs = boost::filesystem;
+
 namespace solidity::phaser::test
 {
 
@@ -114,6 +118,63 @@ BOOST_AUTO_TEST_CASE(enumerateOptimisationSteps_should_assing_indices_to_all_ava
 	}
 }
 
+BOOST_AUTO_TEST_CASE(TemporaryDirectory_should_create_and_delete_a_unique_and_empty_directory)
+{
+	fs::path dirPath;
+	{
+		TemporaryDirectory tempDir("temporary-directory-test-");
+		dirPath = tempDir.path();
+
+		BOOST_TEST(dirPath.stem().string().find("temporary-directory-test-") == 0);
+		BOOST_TEST(fs::equivalent(dirPath.parent_path(), fs::temp_directory_path()));
+		BOOST_TEST(fs::is_directory(dirPath));
+		BOOST_TEST(fs::is_empty(dirPath));
+	}
+	BOOST_TEST(!fs::exists(dirPath));
+}
+
+BOOST_AUTO_TEST_CASE(TemporaryDirectory_should_delete_its_directory_even_if_not_empty)
+{
+	fs::path dirPath;
+	{
+		TemporaryDirectory tempDir("temporary-directory-test-");
+		dirPath = tempDir.path();
+
+		BOOST_TEST(fs::is_directory(dirPath));
+
+		{
+			ofstream tmpFile((dirPath / "test-file.txt").string());
+			tmpFile << "Delete me!" << endl;
+		}
+		assert(fs::is_regular_file(dirPath / "test-file.txt"));
+	}
+	BOOST_TEST(!fs::exists(dirPath / "test-file.txt"));
+}
+
+BOOST_AUTO_TEST_CASE(TemporaryDirectory_memberPath_should_construct_paths_relative_to_the_temporary_directory)
+{
+	TemporaryDirectory tempDir("temporary-directory-test-");
+
+	BOOST_TEST(fs::equivalent(tempDir.memberPath(""), tempDir.path()));
+	BOOST_TEST(fs::equivalent(tempDir.memberPath("."), tempDir.path() / fs::path(".")));
+	BOOST_TEST(fs::equivalent(tempDir.memberPath(".."), tempDir.path() / fs::path("..")));
+
+	// NOTE: fs::equivalent() only works with paths that actually exist
+	{
+		ofstream file;
+		file.open(tempDir.memberPath("file.txt"), ios::out);
+	}
+	BOOST_TEST(fs::equivalent(tempDir.memberPath("file.txt"), tempDir.path() / fs::path("file.txt")));
+
+	{
+		fs::create_directories(tempDir.memberPath("a/b/"));
+
+		ofstream file;
+		file.open(tempDir.memberPath("a/b/file.txt"), ios::out);
+	}
+	BOOST_TEST(fs::equivalent(tempDir.memberPath("a/b/file.txt"), tempDir.path() / fs::path("a") / fs::path("b") / fs::path("file.txt")));
+}
+
 BOOST_AUTO_TEST_CASE(stripWhitespace_should_remove_all_whitespace_characters_from_a_string)
 {
 	BOOST_TEST(stripWhitespace("") == "");