add encoding tests (#502)

* add encoding tests

* format

tests/z_api_encoding_test.c

@@ -0,0 +1,82 @@
+#include <assert.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "zenoh.h"
+
+#undef NDEBUG
+#include <assert.h>
+
+void test_null_encoding(void) {
+    z_owned_encoding_t e;
+    z_encoding_null(&e);
+    assert(!z_encoding_check(&e));
+    z_encoding_drop(z_move(e));
+}
+
+void test_encoding_without_id(void) {
+    z_owned_encoding_t e1;
+    z_encoding_from_str(&e1, "my_encoding");
+    assert(z_encoding_check(&e1));
+    z_owned_string_t s;
+    z_encoding_to_string(z_encoding_loan(&e1), &s);
+    assert(strncmp("zenoh/bytes;my_encoding", z_string_data(z_string_loan(&s)), z_string_len(z_string_loan(&s))) == 0);
+    z_encoding_drop(z_move(e1));
+    z_string_drop(z_move(s));
+
+    z_owned_encoding_t e2;
+    z_encoding_from_substr(&e2, "my_encoding", 4);
+    assert(z_encoding_check(&e2));
+
+    z_encoding_to_string(z_encoding_loan(&e2), &s);
+    assert(strncmp("zenoh/bytes;my_e", z_string_data(z_string_loan(&s)), z_string_len(z_string_loan(&s))) == 0);
+    z_encoding_drop(z_move(e2));
+    z_string_drop(z_move(s));
+}
+
+void test_encoding_with_id(void) {
+    z_owned_encoding_t e1;
+    z_encoding_from_str(&e1, "zenoh/string;utf8");
+    assert(z_encoding_check(&e1));
+    z_owned_string_t s;
+    z_encoding_to_string(z_encoding_loan(&e1), &s);
+    assert(strncmp("zenoh/string;utf8", z_string_data(z_string_loan(&s)), z_string_len(z_string_loan(&s))) == 0);
+    z_encoding_drop(z_move(e1));
+    z_string_drop(z_move(s));
+
+    z_owned_encoding_t e2;
+    z_encoding_from_substr(&e2, "zenoh/string;utf8", 15);
+    assert(z_encoding_check(&e2));
+
+    z_encoding_to_string(z_encoding_loan(&e2), &s);
+    assert(strncmp("zenoh/string;utf8", z_string_data(z_string_loan(&s)), z_string_len(z_string_loan(&s))) == 0);
+    z_encoding_drop(z_move(e2));
+    z_string_drop(z_move(s));
+
+    z_owned_encoding_t e3;
+    z_encoding_from_str(&e3, "custom_id;custom_schema");
+    assert(z_encoding_check(&e3));
+
+    z_encoding_to_string(z_encoding_loan(&e3), &s);
+    assert(strncmp("zenoh/bytes;custom_id;custom_schema", z_string_data(z_string_loan(&s)),
+                   z_string_len(z_string_loan(&s))) == 0);
+    z_encoding_drop(z_move(e3));
+    z_string_drop(z_move(s));
+
+    z_owned_encoding_t e4;
+    z_encoding_from_substr(&e4, "custom_id;custom_schema", 16);
+    assert(z_encoding_check(&e4));
+
+    z_encoding_to_string(z_encoding_loan(&e4), &s);
+    assert(strncmp("zenoh/bytes;custom_id;custom", z_string_data(z_string_loan(&s)), z_string_len(z_string_loan(&s))) ==
+           0);
+    z_encoding_drop(z_move(e4));
+    z_string_drop(z_move(s));
+}
+
+int main(int argc, char **argv) {
+    test_null_encoding();
+    test_encoding_without_id();
+    test_encoding_with_id();
+}