Clean up GIT_UNUSED macros on all platforms

It turns out that commit 31e9cfc4cbcaf1b38cdd3dbe3282a8f57e5366a5
did not fix the GIT_USUSED behavior on all platforms.  This commit
walks through and really cleans things up more thoroughly, getting
rid of the unnecessary stuff.

To remove the use of some GIT_UNUSED, I ended up adding a couple
of new iterators for hashtables that allow you to iterator just
over keys or just over values.

In making this change, I found a bug in the clar tests (where we
were doing *count++ but meant to do (*count)++ to increment the
value).  I fixed that but then found the test failing because it
was not really using an empty repo.  So, I took some of the code
that I wrote for iterator testing and moved it to clar_helpers.c,
then made use of that to make it easier to open fixtures on a
per test basis even within a single test file.

5 files changed, 16 insertions, 68 deletions

diff --git a/tests-clar/diff/blob.c b/tests-clar/diff/blob.c
index 7aa8ceb22..bdfe8baaf 100644
--- a/tests-clar/diff/blob.c
+++ b/tests-clar/diff/blob.c
@@ -5,17 +5,12 @@ static git_repository *g_repo = NULL;
 
 void test_diff_blob__initialize(void)
 {
-	cl_fixture_sandbox("attr");
-	cl_git_pass(p_rename("attr/.gitted", "attr/.git"));
-	cl_git_pass(p_rename("attr/gitattributes", "attr/.gitattributes"));
-	cl_git_pass(git_repository_open(&g_repo, "attr/.git"));
+	g_repo = cl_git_sandbox_init("attr");
 }
 
 void test_diff_blob__cleanup(void)
 {
-	git_repository_free(g_repo);
-	g_repo = NULL;
-	cl_fixture_cleanup("attr");
+	cl_git_sandbox_cleanup();
 }
 
 void test_diff_blob__0(void)
diff --git a/tests-clar/diff/index.c b/tests-clar/diff/index.c
index 0941c7c21..171815df5 100644
--- a/tests-clar/diff/index.c
+++ b/tests-clar/diff/index.c
@@ -5,16 +5,12 @@ static git_repository *g_repo = NULL;
 
 void test_diff_index__initialize(void)
 {
-	cl_fixture_sandbox("status");
-	cl_git_pass(p_rename("status/.gitted", "status/.git"));
-	cl_git_pass(git_repository_open(&g_repo, "status/.git"));
+	g_repo = cl_git_sandbox_init("status");
 }
 
 void test_diff_index__cleanup(void)
 {
-	git_repository_free(g_repo);
-	g_repo = NULL;
-	cl_fixture_cleanup("status");
+	cl_git_sandbox_cleanup();
 }
 
 void test_diff_index__0(void)
diff --git a/tests-clar/diff/iterator.c b/tests-clar/diff/iterator.c
index 1ad126ca8..3953fd83f 100644
--- a/tests-clar/diff/iterator.c
+++ b/tests-clar/diff/iterator.c
@@ -2,37 +2,6 @@
 #include "diff_helpers.h"
 #include "iterator.h"
 
-static git_repository *g_repo = NULL;
-static const char *g_sandbox = NULL;
-
-static void setup_sandbox(const char *sandbox)
-{
-	cl_fixture_sandbox(sandbox);
-	g_sandbox = sandbox;
-
-	p_chdir(sandbox);
-	cl_git_pass(p_rename(".gitted", ".git"));
-	if (p_access("gitattributes", F_OK) == 0)
-		cl_git_pass(p_rename("gitattributes", ".gitattributes"));
-	if (p_access("gitignore", F_OK) == 0)
-		cl_git_pass(p_rename("gitignore", ".gitignore"));
-	p_chdir("..");
-
-	cl_git_pass(git_repository_open(&g_repo, sandbox));
-}
-
-static void cleanup_sandbox(void)
-{
-	if (g_repo) {
-		git_repository_free(g_repo);
-		g_repo = NULL;
-	}
-	if (g_sandbox) {
-		cl_fixture_cleanup(g_sandbox);
-		g_sandbox = NULL;
-	}
-}
-
 void test_diff_iterator__initialize(void)
 {
 	/* since we are doing tests with different sandboxes, defer setup
@@ -44,7 +13,7 @@ void test_diff_iterator__initialize(void)
 
 void test_diff_iterator__cleanup(void)
 {
-	cleanup_sandbox();
+	cl_git_sandbox_cleanup();
 }
 
 
@@ -60,11 +29,10 @@ static void tree_iterator_test(
 	git_iterator *i;
 	const git_index_entry *entry;
 	int count = 0;
+	git_repository *repo = cl_git_sandbox_init(sandbox);
 
-	setup_sandbox(sandbox);
-
-	cl_assert(t = resolve_commit_oid_to_tree(g_repo, treeish));
-	cl_git_pass(git_iterator_for_tree(g_repo, t, &i));
+	cl_assert(t = resolve_commit_oid_to_tree(repo, treeish));
+	cl_git_pass(git_iterator_for_tree(repo, t, &i));
 	cl_git_pass(git_iterator_current(i, &entry));
 
 	while (entry != NULL) {
@@ -183,10 +151,9 @@ static void index_iterator_test(
 	git_iterator *i;
 	const git_index_entry *entry;
 	int count = 0;
+	git_repository *repo = cl_git_sandbox_init(sandbox);
 
-	setup_sandbox(sandbox);
-
-	cl_git_pass(git_iterator_for_index(g_repo, &i));
+	cl_git_pass(git_iterator_for_index(repo, &i));
 	cl_git_pass(git_iterator_current(i, &entry));
 
 	while (entry != NULL) {
@@ -303,10 +270,9 @@ static void workdir_iterator_test(
 	git_iterator *i;
 	const git_index_entry *entry;
 	int count = 0, count_all = 0;
+	git_repository *repo = cl_git_sandbox_init(sandbox);
 
-	setup_sandbox(sandbox);
-
-	cl_git_pass(git_iterator_for_workdir(g_repo, &i));
+	cl_git_pass(git_iterator_for_workdir(repo, &i));
 	cl_git_pass(git_iterator_current(i, &entry));
 
 	while (entry != NULL) {
diff --git a/tests-clar/diff/tree.c b/tests-clar/diff/tree.c
index f5fdfba16..91e1343cc 100644
--- a/tests-clar/diff/tree.c
+++ b/tests-clar/diff/tree.c
@@ -5,17 +5,12 @@ static git_repository *g_repo = NULL;
 
 void test_diff_tree__initialize(void)
 {
-	cl_fixture_sandbox("attr");
-	cl_git_pass(p_rename("attr/.gitted", "attr/.git"));
-	cl_git_pass(p_rename("attr/gitattributes", "attr/.gitattributes"));
-	cl_git_pass(git_repository_open(&g_repo, "attr/.git"));
+	g_repo = cl_git_sandbox_init("attr");
 }
 
 void test_diff_tree__cleanup(void)
 {
-	git_repository_free(g_repo);
-	g_repo = NULL;
-	cl_fixture_cleanup("attr");
+	cl_git_sandbox_cleanup();
 }
 
 void test_diff_tree__0(void)
diff --git a/tests-clar/diff/workdir.c b/tests-clar/diff/workdir.c
index 7312a72a7..28cfa23e2 100644
--- a/tests-clar/diff/workdir.c
+++ b/tests-clar/diff/workdir.c
@@ -5,16 +5,12 @@ static git_repository *g_repo = NULL;
 
 void test_diff_workdir__initialize(void)
 {
-	cl_fixture_sandbox("status");
-	cl_git_pass(p_rename("status/.gitted", "status/.git"));
-	cl_git_pass(git_repository_open(&g_repo, "status/.git"));
+	g_repo = cl_git_sandbox_init("status");
 }
 
 void test_diff_workdir__cleanup(void)
 {
-	git_repository_free(g_repo);
-	g_repo = NULL;
-	cl_fixture_cleanup("status");
+	cl_git_sandbox_cleanup();
 }
 
 void test_diff_workdir__to_index(void)