From a409c1a882e65878476f58d033321eb05e163ab5 Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Mon, 1 Jul 2024 17:22:26 +0200
Subject: [PATCH] Start unit testing GitFileSystemObjectSink

---
 tests/unit/libfetchers/git-utils.cc | 90 +++++++++++++++++++++++++++++
 tests/unit/libfetchers/local.mk     |  2 +-
 2 files changed, 91 insertions(+), 1 deletion(-)
 create mode 100644 tests/unit/libfetchers/git-utils.cc

diff --git a/tests/unit/libfetchers/git-utils.cc b/tests/unit/libfetchers/git-utils.cc
new file mode 100644
index 000000000..c007d1c3c
--- /dev/null
+++ b/tests/unit/libfetchers/git-utils.cc
@@ -0,0 +1,90 @@
+#include "git-utils.hh"
+#include "file-system.hh"
+#include "gmock/gmock.h"
+#include <git2/global.h>
+#include <git2/repository.h>
+#include <git2/types.h>
+#include <gtest/gtest.h>
+#include "fs-sink.hh"
+#include "serialise.hh"
+
+namespace nix {
+
+class GitUtilsTest : public ::testing::Test
+{
+    // We use a single repository for all tests.
+    Path tmpDir;
+    std::unique_ptr<AutoDelete> delTmpDir;
+
+public:
+    void SetUp() override
+    {
+        tmpDir = createTempDir();
+        delTmpDir = std::make_unique<AutoDelete>(tmpDir, true);
+
+        // Create the repo with libgit2
+        git_libgit2_init();
+        git_repository * repo = nullptr;
+        auto r = git_repository_init(&repo, tmpDir.c_str(), 0);
+        ASSERT_EQ(r, 0);
+        git_repository_free(repo);
+    }
+
+    void TearDown() override
+    {
+        // Destroy the AutoDelete, triggering removal
+        // not AutoDelete::reset(), which would cancel the deletion.
+        delTmpDir.reset();
+    }
+
+    ref<GitRepo> openRepo()
+    {
+        return GitRepo::openRepo(tmpDir, true, false);
+    }
+};
+
+void writeString(CreateRegularFileSink & fileSink, std::string contents, bool executable)
+{
+    if (executable)
+        fileSink.isExecutable();
+    fileSink.preallocateContents(contents.size());
+    fileSink(contents);
+}
+
+TEST_F(GitUtilsTest, sink_basic)
+{
+    auto repo = openRepo();
+    auto sink = repo->getFileSystemObjectSink();
+
+    // TODO/Question: It seems a little odd that we use the tarball-like convention of requiring a top-level directory
+    // here
+    //                The sync method does not document this behavior, should probably renamed because it's not very
+    //                general, and I can't imagine that "non-conventional" archives or any other source to be handled by
+    //                this sink.
+
+    sink->createDirectory("foo-1.1");
+
+    sink->createRegularFile(
+        "foo-1.1/hello", [](CreateRegularFileSink & fileSink) { writeString(fileSink, "hello world", false); });
+    sink->createRegularFile("foo-1.1/bye", [](CreateRegularFileSink & fileSink) {
+        writeString(fileSink, "thanks for all the fish", false);
+    });
+    sink->createSymlink("foo-1.1/bye-link", "bye");
+    sink->createDirectory("foo-1.1/empty");
+    sink->createDirectory("foo-1.1/links");
+    sink->createHardlink("foo-1.1/links/foo", CanonPath("foo-1.1/hello"));
+
+    // sink->createHardlink("foo-1.1/links/foo-2", CanonPath("foo-1.1/hello"));
+
+    auto result = sink->sync();
+    auto accessor = repo->getAccessor(result, false);
+    auto entries = accessor->readDirectory(CanonPath::root);
+    ASSERT_EQ(entries.size(), 5);
+    ASSERT_EQ(accessor->readFile(CanonPath("hello")), "hello world");
+    ASSERT_EQ(accessor->readFile(CanonPath("bye")), "thanks for all the fish");
+    ASSERT_EQ(accessor->readLink(CanonPath("bye-link")), "bye");
+    ASSERT_EQ(accessor->readDirectory(CanonPath("empty")).size(), 0);
+    ASSERT_EQ(accessor->readFile(CanonPath("links/foo")), "hello world");
+};
+
+} // namespace nix
diff --git a/tests/unit/libfetchers/local.mk b/tests/unit/libfetchers/local.mk
index d576d28f3..f4e56a501 100644
--- a/tests/unit/libfetchers/local.mk
+++ b/tests/unit/libfetchers/local.mk
@@ -29,7 +29,7 @@ libfetchers-tests_LIBS = \
     libstore-test-support libutil-test-support \
     libfetchers libstore libutil
 
-libfetchers-tests_LDFLAGS := -lrapidcheck $(GTEST_LIBS)
+libfetchers-tests_LDFLAGS := -lrapidcheck $(GTEST_LIBS) $(LIBGIT2_LIBS)
 
 ifdef HOST_WINDOWS
   # Increase the default reserved stack size to 65 MB so Nix doesn't run out of space