str: introduce `git_str` for internal, `git_buf` is externalethomson/gitstr

libgit2 has two distinct requirements that were previously solved by
`git_buf`.  We require:

1. A general purpose string class that provides a number of utility APIs
   for manipulating data (eg, concatenating, truncating, etc).
2. A structure that we can use to return strings to callers that they
   can take ownership of.

By using a single class (`git_buf`) for both of these purposes, we have
confused the API to the point that refactorings are difficult and
reasoning about correctness is also difficult.

Move the utility class `git_buf` to be called `git_str`: this represents
its general purpose, as an internal string buffer class.  The name also
is an homage to Junio Hamano ("gitstr").

The public API remains `git_buf`, and has a much smaller footprint.  It
is generally only used as an "out" param with strict requirements that
follow the documentation.  (Exceptions exist for some legacy APIs to
avoid breaking callers unnecessarily.)

Utility functions exist to convert a user-specified `git_buf` to a
`git_str` so that we can call internal functions, then converting it
back again.

1 files changed, 1225 insertions, 0 deletions

diff --git a/tests/core/gitstr.c b/tests/core/gitstr.c
new file mode 100644
index 000000000..0a624e28c
--- /dev/null
+++ b/tests/core/gitstr.c
@@ -0,0 +1,1225 @@
+#include "clar_libgit2.h"
+#include "git2/sys/hashsig.h"
+#include "futils.h"
+
+#define TESTSTR "Have you seen that? Have you seeeen that??"
+const char *test_string = TESTSTR;
+const char *test_string_x2 = TESTSTR TESTSTR;
+
+#define TESTSTR_4096 REP1024("1234")
+#define TESTSTR_8192 REP1024("12341234")
+const char *test_4096 = TESTSTR_4096;
+const char *test_8192 = TESTSTR_8192;
+
+/* test basic data concatenation */
+void test_core_gitstr__0(void)
+{
+	git_str buf = GIT_STR_INIT;
+
+	cl_assert(buf.size == 0);
+
+	git_str_puts(&buf, test_string);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(test_string, git_str_cstr(&buf));
+
+	git_str_puts(&buf, test_string);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(test_string_x2, git_str_cstr(&buf));
+
+	git_str_dispose(&buf);
+}
+
+/* test git_str_printf */
+void test_core_gitstr__1(void)
+{
+	git_str buf = GIT_STR_INIT;
+
+	git_str_printf(&buf, "%s %s %d ", "shoop", "da", 23);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s("shoop da 23 ", git_str_cstr(&buf));
+
+	git_str_printf(&buf, "%s %d", "woop", 42);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s("shoop da 23 woop 42", git_str_cstr(&buf));
+
+	git_str_dispose(&buf);
+}
+
+/* more thorough test of concatenation options */
+void test_core_gitstr__2(void)
+{
+	git_str buf = GIT_STR_INIT;
+	int i;
+	char data[128];
+
+	cl_assert(buf.size == 0);
+
+	/* this must be safe to do */
+	git_str_dispose(&buf);
+	cl_assert(buf.size == 0);
+	cl_assert(buf.asize == 0);
+
+	/* empty buffer should be empty string */
+	cl_assert_equal_s("", git_str_cstr(&buf));
+	cl_assert(buf.size == 0);
+	/* cl_assert(buf.asize == 0); -- should not assume what git_str does */
+
+	/* free should set us back to the beginning */
+	git_str_dispose(&buf);
+	cl_assert(buf.size == 0);
+	cl_assert(buf.asize == 0);
+
+	/* add letter */
+	git_str_putc(&buf, '+');
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s("+", git_str_cstr(&buf));
+
+	/* add letter again */
+	git_str_putc(&buf, '+');
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s("++", git_str_cstr(&buf));
+
+	/* let's try that a few times */
+	for (i = 0; i < 16; ++i) {
+		git_str_putc(&buf, '+');
+		cl_assert(git_str_oom(&buf) == 0);
+	}
+	cl_assert_equal_s("++++++++++++++++++", git_str_cstr(&buf));
+
+	git_str_dispose(&buf);
+
+	/* add data */
+	git_str_put(&buf, "xo", 2);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s("xo", git_str_cstr(&buf));
+
+	/* add letter again */
+	git_str_put(&buf, "xo", 2);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s("xoxo", git_str_cstr(&buf));
+
+	/* let's try that a few times */
+	for (i = 0; i < 16; ++i) {
+		git_str_put(&buf, "xo", 2);
+		cl_assert(git_str_oom(&buf) == 0);
+	}
+	cl_assert_equal_s("xoxoxoxoxoxoxoxoxoxoxoxoxoxoxoxoxoxo",
+					   git_str_cstr(&buf));
+
+	git_str_dispose(&buf);
+
+	/* set to string */
+	git_str_sets(&buf, test_string);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(test_string, git_str_cstr(&buf));
+
+	/* append string */
+	git_str_puts(&buf, test_string);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(test_string_x2, git_str_cstr(&buf));
+
+	/* set to string again (should overwrite - not append) */
+	git_str_sets(&buf, test_string);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(test_string, git_str_cstr(&buf));
+
+	/* test clear */
+	git_str_clear(&buf);
+	cl_assert_equal_s("", git_str_cstr(&buf));
+
+	git_str_dispose(&buf);
+
+	/* test extracting data into buffer */
+	git_str_puts(&buf, REP4("0123456789"));
+	cl_assert(git_str_oom(&buf) == 0);
+
+	git_str_copy_cstr(data, sizeof(data), &buf);
+	cl_assert_equal_s(REP4("0123456789"), data);
+	git_str_copy_cstr(data, 11, &buf);
+	cl_assert_equal_s("0123456789", data);
+	git_str_copy_cstr(data, 3, &buf);
+	cl_assert_equal_s("01", data);
+	git_str_copy_cstr(data, 1, &buf);
+	cl_assert_equal_s("", data);
+
+	git_str_copy_cstr(data, sizeof(data), &buf);
+	cl_assert_equal_s(REP4("0123456789"), data);
+
+	git_str_sets(&buf, REP256("x"));
+	git_str_copy_cstr(data, sizeof(data), &buf);
+	/* since sizeof(data) == 128, only 127 bytes should be copied */
+	cl_assert_equal_s(REP4(REP16("x")) REP16("x") REP16("x")
+					   REP16("x") "xxxxxxxxxxxxxxx", data);
+
+	git_str_dispose(&buf);
+
+	git_str_copy_cstr(data, sizeof(data), &buf);
+	cl_assert_equal_s("", data);
+}
+
+/* let's do some tests with larger buffers to push our limits */
+void test_core_gitstr__3(void)
+{
+	git_str buf = GIT_STR_INIT;
+
+	/* set to string */
+	git_str_set(&buf, test_4096, 4096);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(test_4096, git_str_cstr(&buf));
+
+	/* append string */
+	git_str_puts(&buf, test_4096);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(test_8192, git_str_cstr(&buf));
+
+	/* set to string again (should overwrite - not append) */
+	git_str_set(&buf, test_4096, 4096);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(test_4096, git_str_cstr(&buf));
+
+	git_str_dispose(&buf);
+}
+
+/* let's try some producer/consumer tests */
+void test_core_gitstr__4(void)
+{
+	git_str buf = GIT_STR_INIT;
+	int i;
+
+	for (i = 0; i < 10; ++i) {
+		git_str_puts(&buf, "1234"); /* add 4 */
+		cl_assert(git_str_oom(&buf) == 0);
+		git_str_consume(&buf, buf.ptr + 2); /* eat the first two */
+		cl_assert(strlen(git_str_cstr(&buf)) == (size_t)((i + 1) * 2));
+	}
+	/* we have appended 1234 10x and removed the first 20 letters */
+	cl_assert_equal_s("12341234123412341234", git_str_cstr(&buf));
+
+	git_str_consume(&buf, NULL);
+	cl_assert_equal_s("12341234123412341234", git_str_cstr(&buf));
+
+	git_str_consume(&buf, "invalid pointer");
+	cl_assert_equal_s("12341234123412341234", git_str_cstr(&buf));
+
+	git_str_consume(&buf, buf.ptr);
+	cl_assert_equal_s("12341234123412341234", git_str_cstr(&buf));
+
+	git_str_consume(&buf, buf.ptr + 1);
+	cl_assert_equal_s("2341234123412341234", git_str_cstr(&buf));
+
+	git_str_consume(&buf, buf.ptr + buf.size);
+	cl_assert_equal_s("", git_str_cstr(&buf));
+
+	git_str_dispose(&buf);
+}
+
+
+static void
+check_buf_append(
+	const char* data_a,
+	const char* data_b,
+	const char* expected_data,
+	size_t expected_size,
+	size_t expected_asize)
+{
+	git_str tgt = GIT_STR_INIT;
+
+	git_str_sets(&tgt, data_a);
+	cl_assert(git_str_oom(&tgt) == 0);
+	git_str_puts(&tgt, data_b);
+	cl_assert(git_str_oom(&tgt) == 0);
+	cl_assert_equal_s(expected_data, git_str_cstr(&tgt));
+	cl_assert_equal_i(tgt.size, expected_size);
+	if (expected_asize > 0)
+		cl_assert_equal_i(tgt.asize, expected_asize);
+
+	git_str_dispose(&tgt);
+}
+
+static void
+check_buf_append_abc(
+	const char* buf_a,
+	const char* buf_b,
+	const char* buf_c,
+	const char* expected_ab,
+	const char* expected_abc,
+	const char* expected_abca,
+	const char* expected_abcab,
+	const char* expected_abcabc)
+{
+	git_str buf = GIT_STR_INIT;
+
+	git_str_sets(&buf, buf_a);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(buf_a, git_str_cstr(&buf));
+
+	git_str_puts(&buf, buf_b);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(expected_ab, git_str_cstr(&buf));
+
+	git_str_puts(&buf, buf_c);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(expected_abc, git_str_cstr(&buf));
+
+	git_str_puts(&buf, buf_a);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(expected_abca, git_str_cstr(&buf));
+
+	git_str_puts(&buf, buf_b);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(expected_abcab, git_str_cstr(&buf));
+
+	git_str_puts(&buf, buf_c);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(expected_abcabc, git_str_cstr(&buf));
+
+	git_str_dispose(&buf);
+}
+
+/* more variations on append tests */
+void test_core_gitstr__5(void)
+{
+	check_buf_append("", "", "", 0, 0);
+	check_buf_append("a", "", "a", 1, 0);
+	check_buf_append("", "a", "a", 1, 8);
+	check_buf_append("", "a", "a", 1, 8);
+	check_buf_append("a", "b", "ab", 2, 8);
+	check_buf_append("", "abcdefgh", "abcdefgh", 8, 16);
+	check_buf_append("abcdefgh", "", "abcdefgh", 8, 16);
+
+	/* buffer with starting asize will grow to:
+	 *  1 ->  2,  2 ->  3,  3 ->  5,  4 ->  6,  5 ->  8,  6 ->  9,
+	 *  7 -> 11,  8 -> 12,  9 -> 14, 10 -> 15, 11 -> 17, 12 -> 18,
+	 * 13 -> 20, 14 -> 21, 15 -> 23, 16 -> 24, 17 -> 26, 18 -> 27,
+	 * 19 -> 29, 20 -> 30, 21 -> 32, 22 -> 33, 23 -> 35, 24 -> 36,
+	 * ...
+	 * follow sequence until value > target size,
+	 * then round up to nearest multiple of 8.
+	 */
+
+	check_buf_append("abcdefgh", "/", "abcdefgh/", 9, 16);
+	check_buf_append("abcdefgh", "ijklmno", "abcdefghijklmno", 15, 16);
+	check_buf_append("abcdefgh", "ijklmnop", "abcdefghijklmnop", 16, 24);
+	check_buf_append("0123456789", "0123456789",
+					 "01234567890123456789", 20, 24);
+	check_buf_append(REP16("x"), REP16("o"),
+					 REP16("x") REP16("o"), 32, 40);
+
+	check_buf_append(test_4096, "", test_4096, 4096, 4104);
+	check_buf_append(test_4096, test_4096, test_8192, 8192, 8200);
+
+	/* check sequences of appends */
+	check_buf_append_abc("a", "b", "c",
+						 "ab", "abc", "abca", "abcab", "abcabc");
+	check_buf_append_abc("a1", "b2", "c3",
+						 "a1b2", "a1b2c3", "a1b2c3a1",
+						 "a1b2c3a1b2", "a1b2c3a1b2c3");
+	check_buf_append_abc("a1/", "b2/", "c3/",
+						 "a1/b2/", "a1/b2/c3/", "a1/b2/c3/a1/",
+						 "a1/b2/c3/a1/b2/", "a1/b2/c3/a1/b2/c3/");
+}
+
+/* test swap */
+void test_core_gitstr__6(void)
+{
+	git_str a = GIT_STR_INIT;
+	git_str b = GIT_STR_INIT;
+
+	git_str_sets(&a, "foo");
+	cl_assert(git_str_oom(&a) == 0);
+	git_str_sets(&b, "bar");
+	cl_assert(git_str_oom(&b) == 0);
+
+	cl_assert_equal_s("foo", git_str_cstr(&a));
+	cl_assert_equal_s("bar", git_str_cstr(&b));
+
+	git_str_swap(&a, &b);
+
+	cl_assert_equal_s("bar", git_str_cstr(&a));
+	cl_assert_equal_s("foo", git_str_cstr(&b));
+
+	git_str_dispose(&a);
+	git_str_dispose(&b);
+}
+
+
+/* test detach/attach data */
+void test_core_gitstr__7(void)
+{
+	const char *fun = "This is fun";
+	git_str a = GIT_STR_INIT;
+	char *b = NULL;
+
+	git_str_sets(&a, "foo");
+	cl_assert(git_str_oom(&a) == 0);
+	cl_assert_equal_s("foo", git_str_cstr(&a));
+
+	b = git_str_detach(&a);
+
+	cl_assert_equal_s("foo", b);
+	cl_assert_equal_s("", a.ptr);
+	git__free(b);
+
+	b = git_str_detach(&a);
+
+	cl_assert_equal_s(NULL, b);
+	cl_assert_equal_s("", a.ptr);
+
+	git_str_dispose(&a);
+
+	b = git__strdup(fun);
+	git_str_attach(&a, b, 0);
+
+	cl_assert_equal_s(fun, a.ptr);
+	cl_assert(a.size == strlen(fun));
+	cl_assert(a.asize == strlen(fun) + 1);
+
+	git_str_dispose(&a);
+
+	b = git__strdup(fun);
+	git_str_attach(&a, b, strlen(fun) + 1);
+
+	cl_assert_equal_s(fun, a.ptr);
+	cl_assert(a.size == strlen(fun));
+	cl_assert(a.asize == strlen(fun) + 1);
+
+	git_str_dispose(&a);
+}
+
+
+static void
+check_joinbuf_2(
+	const char *a,
+	const char *b,
+	const char *expected)
+{
+	char sep = '/';
+	git_str buf = GIT_STR_INIT;
+
+	git_str_join(&buf, sep, a, b);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(expected, git_str_cstr(&buf));
+	git_str_dispose(&buf);
+}
+
+static void
+check_joinbuf_overlapped(
+	const char *oldval,
+	int ofs_a,
+	const char *b,
+	const char *expected)
+{
+	char sep = '/';
+	git_str buf = GIT_STR_INIT;
+
+	git_str_sets(&buf, oldval);
+	git_str_join(&buf, sep, buf.ptr + ofs_a, b);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(expected, git_str_cstr(&buf));
+	git_str_dispose(&buf);
+}
+
+static void
+check_joinbuf_n_2(
+	const char *a,
+	const char *b,
+	const char *expected)
+{
+	char sep = '/';
+	git_str buf = GIT_STR_INIT;
+
+	git_str_sets(&buf, a);
+	cl_assert(git_str_oom(&buf) == 0);
+
+	git_str_join_n(&buf, sep, 1, b);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(expected, git_str_cstr(&buf));
+
+	git_str_dispose(&buf);
+}
+
+static void
+check_joinbuf_n_4(
+	const char *a,
+	const char *b,
+	const char *c,
+	const char *d,
+	const char *expected)
+{
+	char sep = ';';
+	git_str buf = GIT_STR_INIT;
+	git_str_join_n(&buf, sep, 4, a, b, c, d);
+	cl_assert(git_str_oom(&buf) == 0);
+	cl_assert_equal_s(expected, git_str_cstr(&buf));
+	git_str_dispose(&buf);
+}
+
+/* test join */
+void test_core_gitstr__8(void)
+{
+	git_str a = GIT_STR_INIT;
+
+	git_str_join_n(&a, '/', 1, "foo");
+	cl_assert(git_str_oom(&a) == 0);
+	cl_assert_equal_s("foo", git_str_cstr(&a));
+
+	git_str_join_n(&a, '/', 1, "bar");
+	cl_assert(git_str_oom(&a) == 0);
+	cl_assert_equal_s("foo/bar", git_str_cstr(&a));
+
+	git_str_join_n(&a, '/', 1, "baz");
+	cl_assert(git_str_oom(&a) == 0);
+	cl_assert_equal_s("foo/bar/baz", git_str_cstr(&a));
+
+	git_str_dispose(&a);
+
+	check_joinbuf_2(NULL, "", "");
+	check_joinbuf_2(NULL, "a", "a");
+	check_joinbuf_2(NULL, "/a", "/a");
+	check_joinbuf_2("", "", "");
+	check_joinbuf_2("", "a", "a");
+	check_joinbuf_2("", "/a", "/a");
+	check_joinbuf_2("a", "", "a/");
+	check_joinbuf_2("a", "/", "a/");
+	check_joinbuf_2("a", "b", "a/b");
+	check_joinbuf_2("/", "a", "/a");
+	check_joinbuf_2("/", "", "/");
+	check_joinbuf_2("/a", "/b", "/a/b");
+	check_joinbuf_2("/a", "/b/", "/a/b/");
+	check_joinbuf_2("/a/", "b/", "/a/b/");
+	check_joinbuf_2("/a/", "/b/", "/a/b/");
+	check_joinbuf_2("/a/", "//b/", "/a/b/");
+	check_joinbuf_2("/abcd", "/defg", "/abcd/defg");
+	check_joinbuf_2("/abcd", "/defg/", "/abcd/defg/");
+	check_joinbuf_2("/abcd/", "defg/", "/abcd/defg/");
+	check_joinbuf_2("/abcd/", "/defg/", "/abcd/defg/");
+
+	check_joinbuf_overlapped("abcd", 0, "efg", "abcd/efg");
+	check_joinbuf_overlapped("abcd", 1, "efg", "bcd/efg");
+	check_joinbuf_overlapped("abcd", 2, "efg", "cd/efg");
+	check_joinbuf_overlapped("abcd", 3, "efg", "d/efg");
+	check_joinbuf_overlapped("abcd", 4, "efg", "efg");
+	check_joinbuf_overlapped("abc/", 2, "efg", "c/efg");
+	check_joinbuf_overlapped("abc/", 3, "efg", "/efg");
+	check_joinbuf_overlapped("abc/", 4, "efg", "efg");
+	check_joinbuf_overlapped("abcd", 3, "", "d/");
+	check_joinbuf_overlapped("abcd", 4, "", "");
+	check_joinbuf_overlapped("abc/", 2, "", "c/");
+	check_joinbuf_overlapped("abc/", 3, "", "/");
+	check_joinbuf_overlapped("abc/", 4, "", "");
+
+	check_joinbuf_n_2("", "", "");
+	check_joinbuf_n_2("", "a", "a");
+	check_joinbuf_n_2("", "/a", "/a");
+	check_joinbuf_n_2("a", "", "a/");
+	check_joinbuf_n_2("a", "/", "a/");
+	check_joinbuf_n_2("a", "b", "a/b");
+	check_joinbuf_n_2("/", "a", "/a");
+	check_joinbuf_n_2("/", "", "/");
+	check_joinbuf_n_2("/a", "/b", "/a/b");
+	check_joinbuf_n_2("/a", "/b/", "/a/b/");
+	check_joinbuf_n_2("/a/", "b/", "/a/b/");
+	check_joinbuf_n_2("/a/", "/b/", "/a/b/");
+	check_joinbuf_n_2("/abcd", "/defg", "/abcd/defg");
+	check_joinbuf_n_2("/abcd", "/defg/", "/abcd/defg/");
+	check_joinbuf_n_2("/abcd/", "defg/", "/abcd/defg/");
+	check_joinbuf_n_2("/abcd/", "/defg/", "/abcd/defg/");
+
+	check_joinbuf_n_4("", "", "", "", "");
+	check_joinbuf_n_4("", "a", "", "", "a;");
+	check_joinbuf_n_4("a", "", "", "", "a;");
+	check_joinbuf_n_4("", "", "", "a", "a");
+	check_joinbuf_n_4("a", "b", "", ";c;d;", "a;b;c;d;");
+	check_joinbuf_n_4("a", "b", "", ";c;d", "a;b;c;d");
+	check_joinbuf_n_4("abcd", "efgh", "ijkl", "mnop", "abcd;efgh;ijkl;mnop");
+	check_joinbuf_n_4("abcd;", "efgh;", "ijkl;", "mnop;", "abcd;efgh;ijkl;mnop;");
+	check_joinbuf_n_4(";abcd;", ";efgh;", ";ijkl;", ";mnop;", ";abcd;efgh;ijkl;mnop;");
+}
+
+void test_core_gitstr__9(void)
+{
+	git_str buf = GIT_STR_INIT;
+
+	/* just some exhaustive tests of various separator placement */
+	char *a[] = { "", "-", "a-", "-a", "-a-" };
+	char *b[] = { "", "-", "b-", "-b", "-b-" };
+	char sep[] = { 0, '-', '/' };
+	char *expect_null[] = { "",    "-",     "a-",     "-a",     "-a-",
+							"-",   "--",    "a--",    "-a-",    "-a--",
+							"b-",  "-b-",   "a-b-",   "-ab-",   "-a-b-",
+							"-b",  "--b",   "a--b",   "-a-b",   "-a--b",
+							"-b-", "--b-",  "a--b-",  "-a-b-",  "-a--b-" };
+	char *expect_dash[] = { "",    "-",     "a-",     "-a-",    "-a-",
+							"-",   "-",     "a-",     "-a-",    "-a-",
+							"b-",  "-b-",   "a-b-",   "-a-b-",  "-a-b-",
+							"-b",  "-b",    "a-b",    "-a-b",   "-a-b",
+							"-b-", "-b-",   "a-b-",   "-a-b-",  "-a-b-" };
+	char *expect_slas[] = { "",    "-/",    "a-/",    "-a/",    "-a-/",
+							"-",   "-/-",   "a-/-",   "-a/-",   "-a-/-",
+							"b-",  "-/b-",  "a-/b-",  "-a/b-",  "-a-/b-",
+							"-b",  "-/-b",  "a-/-b",  "-a/-b",  "-a-/-b",
+							"-b-", "-/-b-", "a-/-b-", "-a/-b-", "-a-/-b-" };
+	char **expect_values[] = { expect_null, expect_dash, expect_slas };
+	char separator, **expect;
+	unsigned int s, i, j;
+
+	for (s = 0; s < sizeof(sep) / sizeof(char); ++s) {
+		separator = sep[s];
+		expect = expect_values[s];
+
+		for (j = 0; j < sizeof(b) / sizeof(char*); ++j) {
+			for (i = 0; i < sizeof(a) / sizeof(char*); ++i) {
+				git_str_join(&buf, separator, a[i], b[j]);
+				cl_assert_equal_s(*expect, buf.ptr);
+				expect++;
+			}
+		}
+	}
+
+	git_str_dispose(&buf);
+}
+
+void test_core_gitstr__10(void)
+{
+	git_str a = GIT_STR_INIT;
+
+	cl_git_pass(git_str_join_n(&a, '/', 1, "test"));
+	cl_assert_equal_s(a.ptr, "test");
+	cl_git_pass(git_str_join_n(&a, '/', 1, "string"));
+	cl_assert_equal_s(a.ptr, "test/string");
+	git_str_clear(&a);
+	cl_git_pass(git_str_join_n(&a, '/', 3, "test", "string", "join"));
+	cl_assert_equal_s(a.ptr, "test/string/join");
+	cl_git_pass(git_str_join_n(&a, '/', 2, a.ptr, "more"));
+	cl_assert_equal_s(a.ptr, "test/string/join/test/string/join/more");
+
+	git_str_dispose(&a);
+}
+
+void test_core_gitstr__join3(void)
+{
+	git_str a = GIT_STR_INIT;
+
+	cl_git_pass(git_str_join3(&a, '/', "test", "string", "join"));
+	cl_assert_equal_s("test/string/join", a.ptr);
+	cl_git_pass(git_str_join3(&a, '/', "test/", "string", "join"));
+	cl_assert_equal_s("test/string/join", a.ptr);
+	cl_git_pass(git_str_join3(&a, '/', "test/", "/string", "join"));
+	cl_assert_equal_s("test/string/join", a.ptr);
+	cl_git_pass(git_str_join3(&a, '/', "test/", "/string/", "join"));
+	cl_assert_equal_s("test/string/join", a.ptr);
+	cl_git_pass(git_str_join3(&a, '/', "test/", "/string/", "/join"));
+	cl_assert_equal_s("test/string/join", a.ptr);
+
+	cl_git_pass(git_str_join3(&a, '/', "", "string", "join"));
+	cl_assert_equal_s("string/join", a.ptr);
+	cl_git_pass(git_str_join3(&a, '/', "", "string/", "join"));
+	cl_assert_equal_s("string/join", a.ptr);
+	cl_git_pass(git_str_join3(&a, '/', "", "string/", "/join"));
+	cl_assert_equal_s("string/join", a.ptr);
+
+	cl_git_pass(git_str_join3(&a, '/', "string", "", "join"));
+	cl_assert_equal_s("string/join", a.ptr);
+	cl_git_pass(git_str_join3(&a, '/', "string/", "", "join"));
+	cl_assert_equal_s("string/join", a.ptr);
+	cl_git_pass(git_str_join3(&a, '/', "string/", "", "/join"));
+	cl_assert_equal_s("string/join", a.ptr);
+
+	git_str_dispose(&a);
+}
+
+void test_core_gitstr__11(void)
+{
+	git_str a = GIT_STR_INIT;
+	char *t1[] = { "nothing", "in", "common" };
+	char *t2[] = { "something", "something else", "some other" };
+	char *t3[] = { "something", "some fun", "no fun" };
+	char *t4[] = { "happy", "happier", "happiest" };
+	char *t5[] = { "happiest", "happier", "happy" };
+	char *t6[] = { "no", "nope", "" };
+	char *t7[] = { "", "doesn't matter" };
+
+	cl_git_pass(git_str_common_prefix(&a, t1, 3));
+	cl_assert_equal_s(a.ptr, "");
+
+	cl_git_pass(git_str_common_prefix(&a, t2, 3));
+	cl_assert_equal_s(a.ptr, "some");
+
+	cl_git_pass(git_str_common_prefix(&a, t3, 3));
+	cl_assert_equal_s(a.ptr, "");
+
+	cl_git_pass(git_str_common_prefix(&a, t4, 3));
+	cl_assert_equal_s(a.ptr, "happ");
+
+	cl_git_pass(git_str_common_prefix(&a, t5, 3));
+	cl_assert_equal_s(a.ptr, "happ");
+
+	cl_git_pass(git_str_common_prefix(&a, t6, 3));
+	cl_assert_equal_s(a.ptr, "");
+
+	cl_git_pass(git_str_common_prefix(&a, t7, 3));
+	cl_assert_equal_s(a.ptr, "");
+
+	git_str_dispose(&a);
+}
+
+void test_core_gitstr__rfind_variants(void)
+{
+	git_str a = GIT_STR_INIT;
+	ssize_t len;
+
+	cl_git_pass(git_str_sets(&a, "/this/is/it/"));
+
+	len = (ssize_t)git_str_len(&a);
+
+	cl_assert(git_str_rfind(&a, '/') == len - 1);
+	cl_assert(git_str_rfind_next(&a, '/') == len - 4);
+
+	cl_assert(git_str_rfind(&a, 'i') == len - 3);
+	cl_assert(git_str_rfind_next(&a, 'i') == len - 3);
+
+	cl_assert(git_str_rfind(&a, 'h') == 2);
+	cl_assert(git_str_rfind_next(&a, 'h') == 2);
+
+	cl_assert(git_str_rfind(&a, 'q') == -1);
+	cl_assert(git_str_rfind_next(&a, 'q') == -1);
+
+	git_str_dispose(&a);
+}
+
+void test_core_gitstr__puts_escaped(void)
+{
+	git_str a = GIT_STR_INIT;
+
+	git_str_clear(&a);
+	cl_git_pass(git_str_puts_escaped(&a, "this is a test", "", ""));
+	cl_assert_equal_s("this is a test", a.ptr);
+
+	git_str_clear(&a);
+	cl_git_pass(git_str_puts_escaped(&a, "this is a test", "t", "\\"));
+	cl_assert_equal_s("\\this is a \\tes\\t", a.ptr);
+
+	git_str_clear(&a);
+	cl_git_pass(git_str_puts_escaped(&a, "this is a test", "i ", "__"));
+	cl_assert_equal_s("th__is__ __is__ a__ test", a.ptr);
+
+	git_str_clear(&a);
+	cl_git_pass(git_str_puts_escape_regex(&a, "^match\\s*[A-Z]+.*"));
+	cl_assert_equal_s("\\^match\\\\s\\*\\[A-Z\\]\\+\\.\\*", a.ptr);
+
+	git_str_dispose(&a);
+}
+
+static void assert_unescape(char *expected, char *to_unescape) {
+	git_str buf = GIT_STR_INIT;
+
+	cl_git_pass(git_str_sets(&buf, to_unescape));
+	git_str_unescape(&buf);
+	cl_assert_equal_s(expected, buf.ptr);
+	cl_assert_equal_sz(strlen(expected), buf.size);
+
+	git_str_dispose(&buf);
+}
+
+void test_core_gitstr__unescape(void)
+{
+	assert_unescape("Escaped\\", "Es\\ca\\ped\\");
+	assert_unescape("Es\\caped\\", "Es\\\\ca\\ped\\\\");
+	assert_unescape("\\", "\\");
+	assert_unescape("\\", "\\\\");
+	assert_unescape("", "");
+}
+
+void test_core_gitstr__encode_base64(void)
+{
+	git_str buf = GIT_STR_INIT;
+
+	/*     t  h  i  s
+	 * 0x 74 68 69 73
+     * 0b 01110100 01101000 01101001 01110011
+	 * 0b 011101 000110 100001 101001 011100 110000
+	 * 0x 1d 06 21 29 1c 30
+	 *     d  G  h  p  c  w
+	 */
+	cl_git_pass(git_str_encode_base64(&buf, "this", 4));
+	cl_assert_equal_s("dGhpcw==", buf.ptr);
+
+	git_str_clear(&buf);
+	cl_git_pass(git_str_encode_base64(&buf, "this!", 5));
+	cl_assert_equal_s("dGhpcyE=", buf.ptr);
+
+	git_str_clear(&buf);
+	cl_git_pass(git_str_encode_base64(&buf, "this!\n", 6));
+	cl_assert_equal_s("dGhpcyEK", buf.ptr);
+
+	git_str_dispose(&buf);
+}
+
+void test_core_gitstr__decode_base64(void)
+{
+	git_str buf = GIT_STR_INIT;
+
+	cl_git_pass(git_str_decode_base64(&buf, "dGhpcw==", 8));
+	cl_assert_equal_s("this", buf.ptr);
+
+	git_str_clear(&buf);
+	cl_git_pass(git_str_decode_base64(&buf, "dGhpcyE=", 8));
+	cl_assert_equal_s("this!", buf.ptr);
+
+	git_str_clear(&buf);
+	cl_git_pass(git_str_decode_base64(&buf, "dGhpcyEK", 8));
+	cl_assert_equal_s("this!\n", buf.ptr);
+
+	cl_git_fail(git_str_decode_base64(&buf, "This is not a valid base64 string!!!", 36));
+	cl_assert_equal_s("this!\n", buf.ptr);
+
+	git_str_dispose(&buf);
+}
+
+void test_core_gitstr__encode_base85(void)
+{
+	git_str buf = GIT_STR_INIT;
+
+	cl_git_pass(git_str_encode_base85(&buf, "this", 4));
+	cl_assert_equal_s("bZBXF", buf.ptr);
+	git_str_clear(&buf);
+
+	cl_git_pass(git_str_encode_base85(&buf, "two rnds", 8));
+	cl_assert_equal_s("ba!tca&BaE", buf.ptr);
+	git_str_clear(&buf);
+
+	cl_git_pass(git_str_encode_base85(&buf, "this is base 85 encoded",
+		strlen("this is base 85 encoded")));
+	cl_assert_equal_s("bZBXFAZc?TVqtS-AUHK3Wo~0{WMyOk", buf.ptr);
+	git_str_clear(&buf);
+
+	git_str_dispose(&buf);
+}
+
+void test_core_gitstr__decode_base85(void)
+{
+	git_str buf = GIT_STR_INIT;
+
+	cl_git_pass(git_str_decode_base85(&buf, "bZBXF", 5, 4));
+	cl_assert_equal_sz(4, buf.size);
+	cl_assert_equal_s("this", buf.ptr);
+	git_str_clear(&buf);
+
+	cl_git_pass(git_str_decode_base85(&buf, "ba!tca&BaE", 10, 8));
+	cl_assert_equal_sz(8, buf.size);
+	cl_assert_equal_s("two rnds", buf.ptr);
+	git_str_clear(&buf);
+
+	cl_git_pass(git_str_decode_base85(&buf, "bZBXFAZc?TVqtS-AUHK3Wo~0{WMyOk", 30, 23));
+	cl_assert_equal_sz(23, buf.size);
+	cl_assert_equal_s("this is base 85 encoded", buf.ptr);
+	git_str_clear(&buf);
+
+	git_str_dispose(&buf);
+}
+
+void test_core_gitstr__decode_base85_fails_gracefully(void)
+{
+	git_str buf = GIT_STR_INIT;
+
+	git_str_puts(&buf, "foobar");
+
+	cl_git_fail(git_str_decode_base85(&buf, "invalid charsZZ", 15, 42));
+	cl_git_fail(git_str_decode_base85(&buf, "invalidchars__ ", 15, 42));
+	cl_git_fail(git_str_decode_base85(&buf, "overflowZZ~~~~~", 15, 42));
+	cl_git_fail(git_str_decode_base85(&buf, "truncated", 9, 42));
+	cl_assert_equal_sz(6, buf.size);
+	cl_assert_equal_s("foobar", buf.ptr);
+
+	git_str_dispose(&buf);
+}
+
+void test_core_gitstr__classify_with_utf8(void)
+{
+	char *data0 = "Simple text\n";
+	size_t data0len = 12;
+	char *data1 = "Is that UTF-8 data I see…\nYep!\n";
+	size_t data1len = 31;
+	char *data2 = "Internal NUL!!!\000\n\nI see you!\n";
+	size_t data2len = 29;
+	char *data3 = "\xef\xbb\xbfThis is UTF-8 with a BOM.\n";
+	size_t data3len = 20;
+	git_str b;
+
+	b.ptr = data0; b.size = b.asize = data0len;
+	cl_assert(!git_str_is_binary(&b));
+	cl_assert(!git_str_contains_nul(&b));
+
+	b.ptr = data1; b.size = b.asize = data1len;
+	cl_assert(!git_str_is_binary(&b));
+	cl_assert(!git_str_contains_nul(&b));
+
+	b.ptr = data2; b.size = b.asize = data2len;
+	cl_assert(git_str_is_binary(&b));
+	cl_assert(git_str_contains_nul(&b));
+
+	b.ptr = data3; b.size = b.asize = data3len;
+	cl_assert(!git_str_is_binary(&b));
+	cl_assert(!git_str_contains_nul(&b));
+}
+
+#define SIMILARITY_TEST_DATA_1 \
+	"000\n001\n002\n003\n004\n005\n006\n007\n008\n009\n" \
+	"010\n011\n012\n013\n014\n015\n016\n017\n018\n019\n" \
+	"020\n021\n022\n023\n024\n025\n026\n027\n028\n029\n" \
+	"030\n031\n032\n033\n034\n035\n036\n037\n038\n039\n" \
+	"040\n041\n042\n043\n044\n045\n046\n047\n048\n049\n"
+
+void test_core_gitstr__similarity_metric(void)
+{
+	git_hashsig *a, *b;
+	git_str buf = GIT_STR_INIT;
+	int sim;
+
+	/* in the first case, we compare data to itself and expect 100% match */
+
+	cl_git_pass(git_str_sets(&buf, SIMILARITY_TEST_DATA_1));
+	cl_git_pass(git_hashsig_create(&a, buf.ptr, buf.size, GIT_HASHSIG_NORMAL));
+	cl_git_pass(git_hashsig_create(&b, buf.ptr, buf.size, GIT_HASHSIG_NORMAL));
+
+	cl_assert_equal_i(100, git_hashsig_compare(a, b));
+
+	git_hashsig_free(a);
+	git_hashsig_free(b);
+
+	/* if we change just a single byte, how much does that change magnify? */
+
+	cl_git_pass(git_str_sets(&buf, SIMILARITY_TEST_DATA_1));
+	cl_git_pass(git_hashsig_create(&a, buf.ptr, buf.size, GIT_HASHSIG_NORMAL));
+	cl_git_pass(git_str_sets(&buf,
+		"000\n001\n002\n003\n004\n005\n006\n007\n008\n009\n" \
+		"010\n011\n012\n013\n014\n015\n016\n017\n018\n019\n" \
+		"x020x\n021\n022\n023\n024\n025\n026\n027\n028\n029\n" \
+		"030\n031\n032\n033\n034\n035\n036\n037\n038\n039\n" \
+		"040\n041\n042\n043\n044\n045\n046\n047\n048\n049\n"
+		));
+	cl_git_pass(git_hashsig_create(&b, buf.ptr, buf.size, GIT_HASHSIG_NORMAL));
+
+	sim = git_hashsig_compare(a, b);
+
+	cl_assert_in_range(95, sim, 100); /* expect >95% similarity */
+
+	git_hashsig_free(a);
+	git_hashsig_free(b);
+
+	/* let's try comparing data to a superset of itself */
+
+	cl_git_pass(git_str_sets(&buf, SIMILARITY_TEST_DATA_1));
+	cl_git_pass(git_hashsig_create(&a, buf.ptr, buf.size, GIT_HASHSIG_NORMAL));
+	cl_git_pass(git_str_sets(&buf, SIMILARITY_TEST_DATA_1
+		"050\n051\n052\n053\n054\n055\n056\n057\n058\n059\n"));
+	cl_git_pass(git_hashsig_create(&b, buf.ptr, buf.size, GIT_HASHSIG_NORMAL));
+
+	sim = git_hashsig_compare(a, b);
+	/* 20% lines added ~= 10% lines changed */
+
+	cl_assert_in_range(85, sim, 95); /* expect similarity around 90% */
+
+	git_hashsig_free(a);
+	git_hashsig_free(b);
+
+	/* what if we keep about half the original data and add half new */
+
+	cl_git_pass(git_str_sets(&buf, SIMILARITY_TEST_DATA_1));
+	cl_git_pass(git_hashsig_create(&a, buf.ptr, buf.size, GIT_HASHSIG_NORMAL));
+	cl_git_pass(git_str_sets(&buf,
+		"000\n001\n002\n003\n004\n005\n006\n007\n008\n009\n" \
+		"010\n011\n012\n013\n014\n015\n016\n017\n018\n019\n" \
+		"020x\n021\n022\n023\n024\n" \
+		"x25\nx26\nx27\nx28\nx29\n" \
+		"x30\nx31\nx32\nx33\nx34\nx35\nx36\nx37\nx38\nx39\n" \
+		"x40\nx41\nx42\nx43\nx44\nx45\nx46\nx47\nx48\nx49\n"
+		));
+	cl_git_pass(git_hashsig_create(&b, buf.ptr, buf.size, GIT_HASHSIG_NORMAL));
+
+	sim = git_hashsig_compare(a, b);
+	/* 50% lines changed */
+
+	cl_assert_in_range(40, sim, 60); /* expect in the 40-60% similarity range */
+
+	git_hashsig_free(a);
+	git_hashsig_free(b);
+
+	/* lastly, let's check that we can hash file content as well */
+
+	cl_git_pass(git_str_sets(&buf, SIMILARITY_TEST_DATA_1));
+	cl_git_pass(git_hashsig_create(&a, buf.ptr, buf.size, GIT_HASHSIG_NORMAL));
+
+	cl_git_pass(git_futils_mkdir("scratch", 0755, GIT_MKDIR_PATH));
+	cl_git_mkfile("scratch/testdata", SIMILARITY_TEST_DATA_1);
+	cl_git_pass(git_hashsig_create_fromfile(
+		&b, "scratch/testdata", GIT_HASHSIG_NORMAL));
+
+	cl_assert_equal_i(100, git_hashsig_compare(a, b));
+
+	git_hashsig_free(a);
+	git_hashsig_free(b);
+
+	git_str_dispose(&buf);
+	git_futils_rmdir_r("scratch", NULL, GIT_RMDIR_REMOVE_FILES);
+}
+
+
+void test_core_gitstr__similarity_metric_whitespace(void)
+{
+	git_hashsig *a, *b;
+	git_str buf = GIT_STR_INIT;
+	int sim, i, j;
+	git_hashsig_option_t opt;
+	const char *tabbed =
+		"	for (s = 0; s < sizeof(sep) / sizeof(char); ++s) {\n"
+		"		separator = sep[s];\n"
+		"		expect = expect_values[s];\n"
+		"\n"
+		"		for (j = 0; j < sizeof(b) / sizeof(char*); ++j) {\n"
+		"			for (i = 0; i < sizeof(a) / sizeof(char*); ++i) {\n"
+		"				git_str_join(&buf, separator, a[i], b[j]);\n"
+		"				cl_assert_equal_s(*expect, buf.ptr);\n"
+		"				expect++;\n"
+		"			}\n"
+		"		}\n"
+		"	}\n";
+	const char *spaced =
+		"   for (s = 0; s < sizeof(sep) / sizeof(char); ++s) {\n"
+		"       separator = sep[s];\n"
+		"       expect = expect_values[s];\n"
+		"\n"
+		"       for (j = 0; j < sizeof(b) / sizeof(char*); ++j) {\n"
+		"           for (i = 0; i < sizeof(a) / sizeof(char*); ++i) {\n"
+		"               git_str_join(&buf, separator, a[i], b[j]);\n"
+		"               cl_assert_equal_s(*expect, buf.ptr);\n"
+		"               expect++;\n"
+		"           }\n"
+		"       }\n"
+		"   }\n";
+	const char *crlf_spaced2 =
+		"  for (s = 0; s < sizeof(sep) / sizeof(char); ++s) {\r\n"
+		"    separator = sep[s];\r\n"
+		"    expect = expect_values[s];\r\n"
+		"\r\n"
+		"    for (j = 0; j < sizeof(b) / sizeof(char*); ++j) {\r\n"
+		"      for (i = 0; i < sizeof(a) / sizeof(char*); ++i) {\r\n"
+		"        git_str_join(&buf, separator, a[i], b[j]);\r\n"
+		"        cl_assert_equal_s(*expect, buf.ptr);\r\n"
+		"        expect++;\r\n"
+		"      }\r\n"
+		"    }\r\n"
+		"  }\r\n";
+	const char *text[3] = { tabbed, spaced, crlf_spaced2 };
+
+	/* let's try variations of our own code with whitespace changes */
+
+	for (opt = GIT_HASHSIG_NORMAL; opt <= GIT_HASHSIG_SMART_WHITESPACE; ++opt) {
+		for (i = 0; i < 3; ++i) {
+			for (j = 0; j < 3; ++j) {
+				cl_git_pass(git_str_sets(&buf, text[i]));
+				cl_git_pass(git_hashsig_create(&a, buf.ptr, buf.size, opt));
+
+				cl_git_pass(git_str_sets(&buf, text[j]));
+				cl_git_pass(git_hashsig_create(&b, buf.ptr, buf.size, opt));
+
+				sim = git_hashsig_compare(a, b);
+
+				if (opt == GIT_HASHSIG_NORMAL) {
+					if (i == j)
+						cl_assert_equal_i(100, sim);
+					else
+						cl_assert_in_range(0, sim, 30); /* pretty different */
+				} else {
+					cl_assert_equal_i(100, sim);
+				}
+
+				git_hashsig_free(a);
+				git_hashsig_free(b);
+			}
+		}
+	}
+
+	git_str_dispose(&buf);
+}
+
+#include "../filter/crlf.h"
+
+#define check_buf(expected,buf) do { \
+	cl_assert_equal_s(expected, buf.ptr); \
+	cl_assert_equal_sz(strlen(expected), buf.size); } while (0)
+
+void test_core_gitstr__lf_and_crlf_conversions(void)
+{
+	git_str src = GIT_STR_INIT, tgt = GIT_STR_INIT;
+
+	/* LF source */
+
+	git_str_sets(&src, "lf\nlf\nlf\nlf\n");
+
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf("lf\r\nlf\r\nlf\r\nlf\r\n", tgt);
+
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf(src.ptr, tgt);
+
+	git_str_sets(&src, "\nlf\nlf\nlf\nlf\nlf");
+
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf("\r\nlf\r\nlf\r\nlf\r\nlf\r\nlf", tgt);
+
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf(src.ptr, tgt);
+
+	/* CRLF source */
+
+	git_str_sets(&src, "crlf\r\ncrlf\r\ncrlf\r\ncrlf\r\n");
+
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf("crlf\r\ncrlf\r\ncrlf\r\ncrlf\r\n", tgt);
+
+	git_str_sets(&src, "crlf\r\ncrlf\r\ncrlf\r\ncrlf\r\n");
+
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf("crlf\ncrlf\ncrlf\ncrlf\n", tgt);
+
+	git_str_sets(&src, "\r\ncrlf\r\ncrlf\r\ncrlf\r\ncrlf\r\ncrlf");
+
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf("\r\ncrlf\r\ncrlf\r\ncrlf\r\ncrlf\r\ncrlf", tgt);
+
+	git_str_sets(&src, "\r\ncrlf\r\ncrlf\r\ncrlf\r\ncrlf\r\ncrlf");
+
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf("\ncrlf\ncrlf\ncrlf\ncrlf\ncrlf", tgt);
+
+	/* CRLF in LF text */
+
+	git_str_sets(&src, "\nlf\nlf\ncrlf\r\nlf\nlf\ncrlf\r\n");
+
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf("\r\nlf\r\nlf\r\ncrlf\r\nlf\r\nlf\r\ncrlf\r\n", tgt);
+
+	git_str_sets(&src, "\nlf\nlf\ncrlf\r\nlf\nlf\ncrlf\r\n");
+
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf("\nlf\nlf\ncrlf\nlf\nlf\ncrlf\n", tgt);
+
+	/* LF in CRLF text */
+
+	git_str_sets(&src, "\ncrlf\r\ncrlf\r\nlf\ncrlf\r\ncrlf");
+
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf("\r\ncrlf\r\ncrlf\r\nlf\r\ncrlf\r\ncrlf", tgt);
+
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf("\ncrlf\ncrlf\nlf\ncrlf\ncrlf", tgt);
+
+	/* bare CR test */
+
+	git_str_sets(&src, "\rcrlf\r\nlf\nlf\ncr\rcrlf\r\nlf\ncr\r");
+
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf("\rcrlf\r\nlf\r\nlf\r\ncr\rcrlf\r\nlf\r\ncr\r", tgt);
+
+	git_str_sets(&src, "\rcrlf\r\nlf\nlf\ncr\rcrlf\r\nlf\ncr\r");
+
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf("\rcrlf\nlf\nlf\ncr\rcrlf\nlf\ncr\r", tgt);
+
+	git_str_sets(&src, "\rcr\r");
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf(src.ptr, tgt);
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf("\rcr\r", tgt);
+
+	git_str_dispose(&src);
+	git_str_dispose(&tgt);
+
+	/* blob correspondence tests */
+
+	git_str_sets(&src, ALL_CRLF_TEXT_RAW);
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf(ALL_CRLF_TEXT_AS_CRLF, tgt);
+	git_str_sets(&src, ALL_CRLF_TEXT_RAW);
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf(ALL_CRLF_TEXT_AS_LF, tgt);
+	git_str_dispose(&src);
+	git_str_dispose(&tgt);
+
+	git_str_sets(&src, ALL_LF_TEXT_RAW);
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf(ALL_LF_TEXT_AS_CRLF, tgt);
+	git_str_sets(&src, ALL_LF_TEXT_RAW);
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf(ALL_LF_TEXT_AS_LF, tgt);
+	git_str_dispose(&src);
+	git_str_dispose(&tgt);
+
+	git_str_sets(&src, MORE_CRLF_TEXT_RAW);
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf(MORE_CRLF_TEXT_AS_CRLF, tgt);
+	git_str_sets(&src, MORE_CRLF_TEXT_RAW);
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf(MORE_CRLF_TEXT_AS_LF, tgt);
+	git_str_dispose(&src);
+	git_str_dispose(&tgt);
+
+	git_str_sets(&src, MORE_LF_TEXT_RAW);
+	cl_git_pass(git_str_lf_to_crlf(&tgt, &src));
+	check_buf(MORE_LF_TEXT_AS_CRLF, tgt);
+	git_str_sets(&src, MORE_LF_TEXT_RAW);
+	cl_git_pass(git_str_crlf_to_lf(&tgt, &src));
+	check_buf(MORE_LF_TEXT_AS_LF, tgt);
+	git_str_dispose(&src);
+	git_str_dispose(&tgt);
+}
+
+void test_core_gitstr__dont_grow_borrowed(void)
+{
+	const char *somestring = "blah blah";
+	git_str buf = GIT_STR_INIT;
+
+	git_str_attach_notowned(&buf, somestring, strlen(somestring) + 1);
+	cl_assert_equal_p(somestring, buf.ptr);
+	cl_assert_equal_i(0, buf.asize);
+	cl_assert_equal_i(strlen(somestring) + 1, buf.size);
+
+	cl_git_fail_with(GIT_EINVALID, git_str_grow(&buf, 1024));
+}
+
+void test_core_gitstr__dont_hit_infinite_loop_when_resizing(void)
+{
+	git_str buf = GIT_STR_INIT;
+
+	cl_git_pass(git_str_puts(&buf, "foobar"));
+	/*
+	 * We do not care whether this succeeds or fails, which
+	 * would depend on platform-specific allocation
+	 * semantics. We only want to know that the function
+	 * actually returns.
+	 */
+	(void)git_str_try_grow(&buf, SIZE_MAX, true);
+
+	git_str_dispose(&buf);
+}
+
+void test_core_gitstr__avoid_printing_into_oom_buffer(void)
+{
+	git_str buf = GIT_STR_INIT;
+
+	/* Emulate OOM situation with a previous allocation */
+	buf.asize = 8;
+	buf.ptr = git_str__oom;
+
+	/*
+	 * Print the same string again. As the buffer still has
+	 * an `asize` of 8 due to the previous print,
+	 * `ENSURE_SIZE` would not try to reallocate the array at
+	 * all. As it didn't explicitly check for `git_str__oom`
+	 * in earlier versions, this would've resulted in it
+	 * returning successfully and thus `git_str_puts` would
+	 * just print into the `git_str__oom` array.
+	 */
+	cl_git_fail(git_str_puts(&buf, "foobar"));
+}