crypto: Add test for the session creation.

src/crypto/olm.rs

@@ -544,6 +544,9 @@ impl std::fmt::Debug for OutboundGroupSession {
 #[cfg(test)]
 mod test {
     use crate::crypto::olm::Account;
+    use olm_rs::session::OlmMessage;
+    use ruma_client_api::r0::keys::SignedKey;
+    use std::collections::HashMap;
 
     #[test]
     fn account_creation() {
@@ -589,4 +592,52 @@ mod test {
         let one_time_keys = account.one_time_keys();
         assert!(one_time_keys.curve25519().is_empty());
     }
+
+    #[test]
+    fn session_creation() {
+        let alice = Account::new();
+        let bob = Account::new();
+        let alice_keys = alice.identity_keys();
+        let one_time_keys = alice.one_time_keys();
+
+        alice.generate_one_time_keys(1);
+        let one_time_keys = alice.one_time_keys();
+        alice.mark_keys_as_published();
+
+        let one_time_key = one_time_keys
+            .curve25519()
+            .iter()
+            .nth(0)
+            .unwrap()
+            .1
+            .to_owned();
+
+        let one_time_key = SignedKey {
+            key: one_time_key,
+            signatures: HashMap::new(),
+        };
+
+        let mut bob_session = bob
+            .create_outbound_session(alice_keys.curve25519(), &one_time_key)
+            .unwrap();
+
+        let plaintext = "Hello world";
+
+        let message = bob_session.encrypt(plaintext);
+
+        let prekey_message = match message.clone() {
+            OlmMessage::PreKey(m) => m,
+            OlmMessage::Message(_) => panic!("Incorrect message type"),
+        };
+
+        let bob_keys = bob.identity_keys();
+        let mut alice_session = alice
+            .create_inbound_session(bob_keys.curve25519(), prekey_message)
+            .unwrap();
+
+        assert_eq!(bob_session.session_id(), alice_session.session_id());
+
+        let decyrpted = alice_session.decrypt(message).unwrap();
+        assert_eq!(plaintext, decyrpted);
+    }
 }