libfetchers: Add unit test

.gitignore

@@ -39,6 +39,9 @@ perl/Makefile.config
 /src/libexpr/nix.tbl
 /src/libexpr/tests/libnixexpr-tests
 
+# /src/libfetchers/
+/src/libfetchers/tests/libnixfetchers-tests
+
 # /src/libstore/
 *.gen.*
 /src/libstore/tests/libnixstore-tests

Makefile

@@ -6,6 +6,7 @@ makefiles = \
   src/libstore/local.mk \
   src/libstore/tests/local.mk \
   src/libfetchers/local.mk \
+  src/libfetchers/tests/local.mk \
   src/libmain/local.mk \
   src/libexpr/local.mk \
   src/libexpr/tests/local.mk \

src/libfetchers/tests/git.cc

@@ -0,0 +1,204 @@
+#include "fetchers.hh"
+#include "input-accessor.hh"
+#include "store-api.hh"
+#include <gtest/gtest.h>
+#include <git2/commit.h>
+#include <git2/errors.h>
+#include <git2/global.h>
+#include <git2/index.h>
+#include <git2/repository.h>
+#include <git2/signature.h>
+#include <git2/tree.h>
+#include <gmock/gmock-matchers.h>
+
+using namespace nix;
+using namespace nix::fetchers;
+
+using testing::SizeIs;
+
+class TmpDir {
+public:
+    const nix::Path dir;
+private:
+    AutoDelete autoDelete;
+
+public:
+    TmpDir() : dir(createTempDir()), autoDelete(dir) { }
+};
+
+class TmpStore : public TmpDir {
+    ref<Store> store;
+public:
+    TmpStore() : store(openStore(dir)) { }
+
+    operator ref<Store>() {
+        return store;
+    }
+};
+
+class TmpRepo : public TmpDir {
+    AutoDelete autoDelete;
+
+public:
+    git_repository *repo = NULL;
+
+    TmpRepo(bool isBare = false)
+    {
+        git_libgit2_init();
+        if (git_repository_init(&repo, dir.c_str(), isBare))
+            throw Error("creating Git repository '%s': %s", dir, git_error_last()->message);
+    }
+    ~TmpRepo() {
+        git_repository_free(repo);
+        git_libgit2_shutdown();
+    }
+
+    // For troubleshooting a test
+    void dump() {
+        (void) system((std::string("exec 2>&1; cd '") + dir + "'; (set -eux; ls -alR; git reflog; git log; git log --graph --oneline --branches --all --color=always; git status;) | cat").c_str());
+    }
+};
+
+static void commitIndexNoParent(git_repository *repo, git_oid &tree_id, git_oid &commit_id) {
+    git_signature *sig;
+	git_tree *tree;
+
+    git_signature_now(&sig, "Test User", "test@example.com");
+
+	if (git_tree_lookup(&tree, repo, &tree_id) < 0)
+		throw Error("Could not look up initial tree: %s", git_error_last()->message);
+
+	if (git_commit_create_v(
+			&commit_id, repo, "HEAD", sig, sig,
+			NULL, "Initial commit", tree, 0) < 0)
+		throw Error("Could not create the initial commit: %s", git_error_last()->message);
+
+	git_tree_free(tree);
+	git_signature_free(sig);
+}
+
+static void initCommit(git_repository *repo) {
+	git_index *index;
+	git_oid tree_id, commit_id;
+
+    if (git_repository_index(&index, repo) < 0)
+		throw Error("Could not open repository index: %s", git_error_last()->message);
+
+	if (git_index_write_tree(&tree_id, index) < 0)
+		throw Error("Unable to write initial tree from index: %s", git_error_last()->message);
+
+	git_index_free(index);
+
+    commitIndexNoParent(repo, tree_id, commit_id);
+}
+
+// I think an empty source would be ok?
+TEST(git, when_the_repo_and_worktree_are_empty__fetchTree_on_the_worktree_returns_an_error) {
+    TmpRepo repo;
+    TmpStore store;
+
+    Attrs attrs;
+    attrs.emplace("type", "git");
+    attrs.emplace("url", std::string("file://") + repo.dir);
+
+    auto input = Input::fromAttrs(std::move(attrs));
+    auto r = input.getAccessor(store);
+
+    InputAccessor &accessor = *r.first;
+
+    ASSERT_THROW({
+        auto root = accessor.root();
+        auto dir = root.readDirectory();
+    }, RestrictedPathError);
+}
+
+// I think an empty source would be ok?
+TEST(git, when_the_repo_head_and_worktree_are_empty__fetchTree_on_the_worktree_returns_an_error) {
+    TmpRepo repo;
+    TmpStore store;
+
+    initCommit(repo.repo);
+
+    Attrs attrs;
+    attrs.emplace("type", "git");
+    attrs.emplace("url", std::string("file://") + repo.dir);
+
+    auto input = Input::fromAttrs(std::move(attrs));
+    auto r = input.getAccessor(store);
+
+    InputAccessor &accessor = *r.first;
+
+    ASSERT_THROW({
+        auto root = accessor.root();
+        auto dir = root.readDirectory();
+    }, RestrictedPathError);
+}
+
+TEST(git, when_the_repo_head_exists_empty_and_worktree_are_empty__fetchTree_on_the_head_returns_an_empty_tree) {
+    TmpRepo repo;
+    TmpStore store;
+
+    initCommit(repo.repo);
+
+    Attrs attrs;
+    attrs.emplace("type", "git");
+    attrs.emplace("ref", "HEAD");
+    attrs.emplace("url", std::string("file://") + repo.dir);
+
+    auto input = Input::fromAttrs(std::move(attrs));
+    auto r = input.getAccessor(store);
+
+    InputAccessor &accessor = *r.first;
+
+    auto root = accessor.root();
+    auto dir = root.readDirectory();
+    ASSERT_THAT(dir, SizeIs(0));
+
+    auto fetched = input.fetchToStore(store);
+    ASSERT_EQ(fetched.first.to_string(), "0ccnxa25whszw7mgbgyzdm4nqc0zwnm8-source");
+}
+
+TEST(git, when_the_head_contains_a_file_and_head_is_requested_return_the_file) {
+    TmpRepo repo;
+    TmpStore store;
+
+
+	git_index *index;
+	git_oid tree_id, commit_id;
+
+    if (git_repository_index(&index, repo.repo) < 0)
+		throw Error("Could not open repository index: %s", git_error_last()->message);
+
+    git_index_entry index_entry;
+    memset(&index_entry, 0, sizeof(index_entry));
+    index_entry.path = "hello";
+    index_entry.mode = GIT_FILEMODE_BLOB;
+
+    if (git_index_add_from_buffer(index, &index_entry, "hi", 2))
+        throw Error("Could not add to index: %s", git_error_last()->message);
+
+	if (git_index_write_tree(&tree_id, index) < 0)
+		throw Error("Unable to write initial tree from index: %s", git_error_last()->message);
+
+	git_index_free(index);
+
+    commitIndexNoParent(repo.repo, tree_id, commit_id);
+
+    Attrs attrs;
+    attrs.emplace("type", "git");
+    attrs.emplace("ref", "HEAD");
+    attrs.emplace("url", std::string("file://") + repo.dir);
+
+    auto input = Input::fromAttrs(std::move(attrs));
+    auto r = input.getAccessor(store);
+
+    InputAccessor &accessor = *r.first;
+
+    auto root = accessor.root();
+    auto dir = root.readDirectory();
+
+    ASSERT_THAT(dir, SizeIs(1));
+
+    auto fetched = input.fetchToStore(store);
+    ASSERT_EQ(fetched.first.to_string(), "5rbhbvyxfxgc6ac9f65qqa7q193qanls-source");
+}

src/libfetchers/tests/local.mk

@@ -0,0 +1,18 @@
+check: libfetchers-tests_RUN
+
+programs += libfetchers-tests
+
+libfetchers-tests_NAME := libnixfetchers-tests
+
+libfetchers-tests_DIR := $(d)
+
+libfetchers-tests_INSTALL_DIR :=
+
+libfetchers-tests_SOURCES := \
+    $(wildcard $(d)/*.cc)
+
+libfetchers-tests_CXXFLAGS += -I src/libfetchers -I src/libutil -I src/libstore -I src/libfetchers/tests
+
+libfetchers-tests_LIBS = libstore-tests libutils-tests libfetchers libutil libstore
+
+libfetchers-tests_LDFLAGS := $(GTEST_LIBS) -lgmock -lgit2