Add Buffer unit tests

- test that writing a buffer with no changes results in the identical
  file being written

.gitignore

@@ -1,3 +1,4 @@
 /.lock-waf*
 /.waf*
 /build/
+/test/tmp/

test/src/TestSupport.cc

@@ -1,6 +1,7 @@
 #include "TestSupport.h"
 #include "File.h"
 #include <stdio.h>
+#include "gtest/gtest.h"
 
 std::shared_ptr<std::vector<uint8_t>> TestSupport::read_file(const char * filename)
 {
@@ -22,3 +23,14 @@ std::shared_ptr<std::vector<uint8_t>> TestSupport::read_file(const char * filena
 
     return buffer;
 }
+
+void TestSupport::compare_files(const char * f1, const char * f2)
+{
+    auto fl1 = read_file(f1);
+    auto fl2 = read_file(f2);
+    ASSERT_EQ(fl1->size(), fl2->size());
+    for (size_t i = 0; i < fl1->size(); i++)
+    {
+        ASSERT_EQ((*fl1)[i], (*fl2)[i]);
+    }
+}

test/src/TestSupport.h

@@ -9,6 +9,7 @@ class TestSupport
 {
 public:
     static std::shared_ptr<std::vector<uint8_t>> read_file(const char * filename);
+    static void compare_files(const char * f1, const char * f2);
 };
 
 #endif

test/src/main.cc

@@ -1,9 +1,12 @@
 #include "gtest/gtest.h"
 #include "System.h"
+#include <sys/stat.h>
+#include <sys/types.h>
 
 int main(int argc, char * argv[])
 {
     ::testing::InitGoogleTest(&argc, argv);
     System::init();
+    mkdir("test/tmp", 0777);
     return RUN_ALL_TESTS();
 }

test/src/test_Buffer.cc

@@ -0,0 +1,23 @@
+#include "gtest/gtest.h"
+#include "Buffer.h"
+#include "TestSupport.h"
+#include "Path.h"
+
+TEST(BufferTest, writes_an_identical_file_to_what_is_loaded_if_no_changes_were_performed)
+{
+    const char * files_to_test[] = {
+        "test/files/empty.txt",
+        "test/files/line_endings/cr_format.txt",
+        "test/files/line_endings/crlf_format.txt",
+        "test/files/line_endings/lf_format.txt",
+        "test/files/no_eol_at_eof.txt",
+    };
+    for (auto e : files_to_test)
+    {
+        Buffer b;
+        ASSERT_TRUE(b.load_from_file(e));
+        ASSERT_TRUE(b.write_to_file("test/tmp/f"));
+        ASSERT_TRUE(Path::is_file("test/tmp/f"));
+        TestSupport::compare_files(e, "test/tmp/f");
+    }
+}