thodg/libgit2

diff --git a/src/transport.c b/src/transport.c
index c0311fa..d390e14 100644
--- a/src/transport.c
+++ b/src/transport.c
@@ -46,34 +46,37 @@ static git_vector custom_transports = GIT_VECTOR_INIT;
 
 #define GIT_TRANSPORT_COUNT (sizeof(transports)/sizeof(transports[0])) - 1
 
-static int transport_find_fn(
-	git_transport_cb *out,
-	const char *url,
-	void **param)
+static transport_definition * transport_find_by_url(const char *url)
 {
 	size_t i = 0;
-	transport_definition *d, *definition = NULL;
+	transport_definition *d;
 
 	/* Find a user transport who wants to deal with this URI */
 	git_vector_foreach(&custom_transports, i, d) {
 		if (strncasecmp(url, d->prefix, strlen(d->prefix)) == 0) {
-			definition = d;
-			break;
+			return d;
 		}
 	}
 
 	/* Find a system transport for this URI */
-	if (!definition) {
-		for (i = 0; i < GIT_TRANSPORT_COUNT; ++i) {
-			d = &transports[i];
-
-			if (strncasecmp(url, d->prefix, strlen(d->prefix)) == 0) {
-				definition = d;
-				break;
-			}
+	for (i = 0; i < GIT_TRANSPORT_COUNT; ++i) {
+		d = &transports[i];
+
+		if (strncasecmp(url, d->prefix, strlen(d->prefix)) == 0) {
+			return d;
 		}
 	}
 
+	return NULL;
+}
+
+static int transport_find_fn(
+	git_transport_cb *out,
+	const char *url,
+	void **param)
+{
+	transport_definition *definition = transport_find_by_url(url);
+
 #ifdef GIT_WIN32
 	/* On Windows, it might not be possible to discern between absolute local
 	 * and ssh paths - first check if this is a valid local path that points
@@ -89,12 +92,15 @@ static int transport_find_fn(
 
 	/* It could be a SSH remote path. Check to see if there's a :
 	 * SSH is an unsupported transport mechanism in this version of libgit2 */
-	if (!definition && strrchr(url, ':'))
-#ifdef GIT_SSH
-		definition = &ssh_transport_definition;
-#else
-		definition = &dummy_transport_definition;
+	if (!definition && strrchr(url, ':')) {
+		// re-search transports again with ssh:// as url so that we can find a third party ssh transport
+		definition = transport_find_by_url("ssh://");
+#ifndef GIT_SSH
+		if (!definition) {
+			definition = &dummy_transport_definition;
+		}
 #endif
+	}
 
 #ifndef GIT_WIN32
 	/* Check to see if the path points to a file on the local file system */
diff --git a/tests/transport/register.c b/tests/transport/register.c
new file mode 100644
index 0000000..937194c
--- /dev/null
+++ b/tests/transport/register.c
@@ -0,0 +1,66 @@
+#include "clar_libgit2.h"
+#include "git2/sys/transport.h"
+
+static git_transport _transport = GIT_TRANSPORT_INIT;
+
+static int dummy_transport(git_transport **transport, git_remote *owner, void *param)
+{
+	*transport = &_transport;
+	GIT_UNUSED(owner);
+	GIT_UNUSED(param);
+	return 0;
+}
+
+void test_transport_register__custom_transport(void)
+{
+	git_transport *transport;
+
+	cl_git_pass(git_transport_register("something", dummy_transport, NULL));
+
+	cl_git_pass(git_transport_new(&transport, NULL, "something://somepath"));
+
+	cl_assert(transport == &_transport);
+
+	cl_git_pass(git_transport_unregister("something"));
+}
+
+void test_transport_register__custom_transport_error_doubleregister(void)
+{
+	cl_git_pass(git_transport_register("something", dummy_transport, NULL));
+
+	cl_git_fail_with(git_transport_register("something", dummy_transport, NULL), GIT_EEXISTS);
+
+	cl_git_pass(git_transport_unregister("something"));
+}
+
+void test_transport_register__custom_transport_error_remove_non_existing(void)
+{
+	cl_git_fail_with(git_transport_unregister("something"), GIT_ENOTFOUND);
+}
+
+void test_transport_register__custom_transport_ssh(void)
+{
+	git_transport *transport;
+
+#ifndef GIT_SSH
+	cl_git_fail_with(git_transport_new(&transport, NULL, "ssh://somehost:somepath"), -1);
+	cl_git_fail_with(git_transport_new(&transport, NULL, "git@somehost:somepath"), -1);
+#else
+	cl_git_pass(git_transport_new(&transport, NULL, "git@somehost:somepath"));
+#endif
+
+	cl_git_pass(git_transport_register("ssh", dummy_transport, NULL));
+
+	cl_git_pass(git_transport_new(&transport, NULL, "git@somehost:somepath"));
+
+	cl_assert(transport == &_transport);
+
+	cl_git_pass(git_transport_unregister("ssh"));
+
+#ifndef GIT_SSH
+	cl_git_fail_with(git_transport_new(&transport, NULL, "ssh://somehost:somepath"), -1);
+	cl_git_fail_with(git_transport_new(&transport, NULL, "git@somehost:somepath"), -1);
+#else
+	cl_git_pass(git_transport_new(&transport, NULL, "git@somehost:somepath"));
+#endif
+}