Token-swap: add tests for all instructions (#455)

* token-swap: Add initialize tests

* Cleanup initialize test using helper struct

* Add deposit tests

* Run cargo fmt

* Add withdraw tests, refactor swap in test

* Add swap tests

* Integrate review feedback

token-swap/program/src/error.rs

@@ -8,41 +8,56 @@ use thiserror::Error;
 #[derive(Clone, Debug, Eq, Error, FromPrimitive, PartialEq)]
 pub enum SwapError {
     /// The account cannot be initialized because it is already being used.
-    #[error("AlreadyInUse")]
+    #[error("Swap account already in use")]
     AlreadyInUse,
     /// The program address provided doesn't match the value generated by the program.
-    #[error("InvalidProgramAddress")]
+    #[error("Invalid program address generated from nonce and key")]
     InvalidProgramAddress,
     /// The owner of the input isn't set to the program address generated by the program.
-    #[error("InvalidOwner")]
+    #[error("Input account owner is not the program address")]
     InvalidOwner,
-    /// The deserialization of the Token state returned something besides State::Token.
-    #[error("ExpectedToken")]
-    ExpectedToken,
-    /// The deserialization of the Token state returned something besides State::Account.
-    #[error("ExpectedAccount")]
+    /// The owner of the pool token output is set to the program address generated by the program.
+    #[error("Output pool account owner cannot be the program address")]
+    InvalidOutputOwner,
+    /// The deserialization of the account returned something besides State::Mint.
+    #[error("Deserialized account is not an SPL Token mint")]
+    ExpectedMint,
+    /// The deserialization of the account returned something besides State::Account.
+    #[error("Deserialized account is not an SPL Token account")]
     ExpectedAccount,
-    /// The initialized pool had a non zero supply.
-    #[error("InvalidSupply")]
+    /// The input token account is empty.
+    #[error("Input token account empty")]
+    EmptySupply,
+    /// The pool token mint has a non-zero supply.
+    #[error("Pool token mint has a non-zero supply")]
     InvalidSupply,
-    /// The initialized token has a delegate.
-    #[error("InvalidDelegate")]
+    /// The provided token account has a delegate.
+    #[error("Token account has a delegate")]
     InvalidDelegate,
-    /// The token swap state is invalid.
-    #[error("InvalidState")]
-    InvalidState,
+    /// The swap info is invalid.
+    #[error("Swap info invalid")]
+    InvalidSwapInfo,
     /// The input token is invalid for swap.
     #[error("InvalidInput")]
     InvalidInput,
+    /// Address of the provided swap token account is incorrect.
+    #[error("Address of the provided swap token account is incorrect")]
+    IncorrectSwapAccount,
+    /// Address of the provided pool token mint is incorrect
+    #[error("Address of the provided pool token mint is incorrect")]
+    IncorrectPoolMint,
     /// The output token is invalid for swap.
     #[error("InvalidOutput")]
     InvalidOutput,
     /// The calculation failed.
     #[error("CalculationFailure")]
     CalculationFailure,
-    /// Invalid instruction number passed in
+    /// Invalid instruction number passed in.
     #[error("Invalid instruction")]
     InvalidInstruction,
+    /// Swap input token accounts have the same mint
+    #[error("Swap input token accounts have the same mint")]
+    RepeatedMint,
 }
 impl From<SwapError> for ProgramError {
     fn from(e: SwapError) -> Self {

token-swap/program/src/instruction.rs

@@ -21,8 +21,8 @@ pub enum SwapInstruction {
     ///   1. `[]` $authority derived from `create_program_address(&[Token-swap account])`
     ///   2. `[]` token_a Account. Must be non zero, owned by $authority.
     ///   3. `[]` token_b Account. Must be non zero, owned by $authority.
-    ///   4. `[writable]` pool Token. Must be empty, owned by $authority.
-    ///   5. `[writable]` Pool Account to deposit the generated tokens, user is the owner.
+    ///   4. `[writable]` Pool Token Mint. Must be empty, owned by $authority.
+    ///   5. `[writable]` Pool Token Account to deposit the minted tokens. Must be empty, owned by user.
     ///   6. '[]` Token program id
     Initialize {
         /// swap pool fee numerator

token-swap/program/src/state.rs

@@ -43,7 +43,7 @@ impl SwapInfo {
         if value.is_initialized {
             Ok(value)
         } else {
-            Err(SwapError::InvalidState.into())
+            Err(SwapError::InvalidSwapInfo.into())
         }
     }
 
@@ -216,6 +216,6 @@ mod tests {
         let unpack_unchecked = SwapInfo::unpack_unchecked(&packed).unwrap();
         assert_eq!(unpack_unchecked, swap_info);
         let err = SwapInfo::unpack(&packed).unwrap_err();
-        assert_eq!(err, SwapError::InvalidState.into());
+        assert_eq!(err, SwapError::InvalidSwapInfo.into());
     }
 }