program-test: Set context without panic (#14997)

* program-test: Fix CPI and multiple instructions

* Whitespace

* Add CPI test in program-test

program-test/src/lib.rs

@@ -74,10 +74,8 @@ thread_local! {
     static INVOKE_CONTEXT: RefCell<Option<(usize, usize)>> = RefCell::new(None);
 }
 fn set_invoke_context(new: &mut dyn InvokeContext) {
-    INVOKE_CONTEXT.with(|invoke_context| {
-        if unsafe { invoke_context.replace(Some(transmute::<_, (usize, usize)>(new))) }.is_some() {
-            panic!("Overwiting invoke context!")
-        }
+    INVOKE_CONTEXT.with(|invoke_context| unsafe {
+        invoke_context.replace(Some(transmute::<_, (usize, usize)>(new)))
     });
 }
 fn get_invoke_context<'a>() -> &'a mut dyn InvokeContext {

program-test/tests/cpi.rs

@@ -0,0 +1,79 @@
+use {
+    solana_program::{
+        account_info::{next_account_info, AccountInfo},
+        entrypoint::ProgramResult,
+        instruction::{AccountMeta, Instruction},
+        msg,
+        program::invoke,
+        pubkey::Pubkey,
+    },
+    solana_program_test::{processor, ProgramTest},
+    solana_sdk::{signature::Signer, transaction::Transaction},
+};
+
+// Process instruction to invoke into another program
+fn invoker_process_instruction(
+    _program_id: &Pubkey,
+    accounts: &[AccountInfo],
+    _input: &[u8],
+) -> ProgramResult {
+    // if we can call `msg!` successfully, then InvokeContext exists as required
+    msg!("Processing invoker instruction before CPI");
+    let account_info_iter = &mut accounts.iter();
+    let invoked_program_info = next_account_info(account_info_iter)?;
+    invoke(
+        &Instruction::new(*invoked_program_info.key, &[0], vec![]),
+        &[invoked_program_info.clone()],
+    )?;
+    msg!("Processing invoker instruction after CPI");
+    Ok(())
+}
+
+// Process instruction to be invoked by another program
+#[allow(clippy::unnecessary_wraps)]
+fn invoked_process_instruction(
+    _program_id: &Pubkey,
+    _accounts: &[AccountInfo],
+    _input: &[u8],
+) -> ProgramResult {
+    // if we can call `msg!` successfully, then InvokeContext exists as required
+    msg!("Processing invoked instruction");
+    Ok(())
+}
+
+#[tokio::test]
+async fn cpi() {
+    let invoker_program_id = Pubkey::new_unique();
+    // Initialize and start the test network
+    let mut program_test = ProgramTest::new(
+        "program-test-fuzz-invoker",
+        invoker_program_id,
+        processor!(invoker_process_instruction),
+    );
+    let invoked_program_id = Pubkey::new_unique();
+    program_test.add_program(
+        "program-test-fuzz-invoked",
+        invoked_program_id,
+        processor!(invoked_process_instruction),
+    );
+
+    let mut test_state = program_test.start_with_context().await;
+    let instructions = vec![Instruction::new(
+        invoker_program_id,
+        &[0],
+        vec![AccountMeta::new_readonly(invoked_program_id, false)],
+    )];
+
+    let transaction = Transaction::new_signed_with_payer(
+        &instructions,
+        Some(&test_state.payer.pubkey()),
+        &[&test_state.payer],
+        test_state.last_blockhash,
+    );
+
+    test_state
+        .banks_client
+        .process_transaction(transaction)
+        .await
+        .unwrap();
+}

program-test/tests/fuzz.rs

@@ -1,8 +1,8 @@
 use {
     solana_banks_client::BanksClient,
     solana_program::{
-        account_info::AccountInfo, entrypoint::ProgramResult, hash::Hash, pubkey::Pubkey,
-        rent::Rent,
+        account_info::AccountInfo, entrypoint::ProgramResult, hash::Hash, instruction::Instruction,
+        msg, pubkey::Pubkey, rent::Rent,
     },
     solana_program_test::{processor, ProgramTest},
     solana_sdk::{
@@ -10,13 +10,14 @@ use {
     },
 };
 
-// Dummy process instruction required to instantiate ProgramTest
 #[allow(clippy::unnecessary_wraps)]
 fn process_instruction(
     _program_id: &Pubkey,
     _accounts: &[AccountInfo],
     _input: &[u8],
 ) -> ProgramResult {
+    // if we can call `msg!` successfully, then InvokeContext exists as required
+    msg!("Processing instruction");
     Ok(())
 }
 
@@ -94,6 +95,7 @@ async fn run_fuzz_instructions(
             program_id,
         );
         instructions.push(instruction);
+        instructions.push(Instruction::new(*program_id, &[0], vec![]));
         signer_keypairs.push(keypair);
     }
     // Process transaction on test network