TESTING_ERROR_HANDLING.md

TeachLink Error Handling - Step-by-Step Testing Guide

Overview

This guide provides a comprehensive step-by-step process to verify that the consistent error handling implementation (#364) has been successfully completed across the TeachLink smart contract.

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Part 1: Compile and Build Verification

Step 1.1: Clean Build

cd contracts/teachlink
./scripts/clean.sh --deep

Expected Result: Build artifacts are removed successfully.

Step 1.2: Build Release WASM

cargo build --release --target wasm32-unknown-unknown -p teachlink-contract

Expected Result:

• Build completes WITHOUT errors
• No warnings about unwrap(), panic!, or expect() in production code
• WASM file generated at: target/wasm32-unknown-unknown/release/teachlink_contract.wasm

Verification Checklist:

• No compilation errors
• No new warnings introduced
• WASM file exists and is valid

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Part 2: Static Analysis Verification

Step 2.1: Check for Remaining Unsafe Patterns

# Check for unwrap() in production code
grep -r "\.unwrap()" contracts/teachlink/src/ --include="*.rs" | grep -v "#\[cfg(test)\]" | grep -v "//.*unwrap" | grep -v "test/"

Expected Result:

• Only entries showing .unwrap_or() with defaults (acceptable)
• No .unwrap() without fallback
• No entries from production code paths

Verification: If any .unwrap() found in production code, FAIL.

Step 2.2: Check for Remaining Panics

# Check for panic! and assert! in production code
grep -rE "panic!|assert!|expect\(" contracts/teachlink/src/ --include="*.rs" | grep -v "#\[cfg(test)\]" | grep -v "//.*" | grep -v "test/"

Expected Result:

• No matches in production code
• assert!() only in test code (#[cfg(test)])
• panic!() only in test code or authorization
• expect() only in test code

Verification: If panic/assert found in production paths, FAIL.

Step 2.3: Verify Result Types

# Check that error-prone functions return Result
grep -rE "pub fn|pub async fn" contracts/teachlink/src/[^t]*.rs | \
  grep -E "(analytics|access_control|reputation|bridge)" --include="*.rs"

Expected Result: Functions that can fail should return Result<T, E>:

• update_participation: Result<(), ReputationError>
• update_course_progress: Result<(), ReputationError>
• rate_contribution: Result<(), ReputationError>
• get_top_chains_by_volume: Result<Vec<_>, AnalyticsError>
• get_top_chains_by_volume_bounded: Result<Vec<_>, AnalyticsError>
• check_role: Result<(), AccessControlError>
• get_token: Result<Address, BridgeError>
• get_admin: Result<Address, BridgeError>

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Part 3: Error Enum Verification

Step 3.1: Verify All Error Enums Exist

grep -E "#\[contracterror\]|pub enum.*Error" contracts/teachlink/src/errors.rs

Expected Result: The following error enums should exist:

• BridgeError (codes 100-147)
• EscrowError (codes 200-227)
• RewardsError (codes 300-309)
• MobilePlatformError (codes 400-407)
• AccessControlError (codes 500-505)
• AnalyticsError (codes 510-514)
• ReputationError (codes 520-525)
• TokenizationError (codes 530-536)
• AdvancedReputationError (codes 540-544)

Step 3.2: Verify Result Type Aliases

grep "pub type.*Result<T>" contracts/teachlink/src/errors.rs

Expected Result: All Result type aliases defined:

• BridgeResult<T>
• EscrowResult<T>
• RewardsResult<T>
• AccessControlResult<T>
• AnalyticsResult<T>
• ReputationResult<T>
• TokenizationResult<T>
• AdvancedReputationResult<T>

Step 3.3: Verify Error Code Ranges

awk '/^#\[contracterror\]/,/^}/' contracts/teachlink/src/errors.rs | \
  grep -E "= [0-9]+" | sort -t'=' -k2 -n

Expected Result: Error codes are:

• Unique (no duplicates)
• In correct ranges (no overlaps)
• Each error has meaningful variant name

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Part 4: Module-Specific Verification

Step 4.1: Analytics Module

# Check analytics.rs for error handling
grep -n "get_top_chains_by_volume" contracts/teachlink/src/analytics.rs

Expected Result:

• Line ~340: pub fn get_top_chains_by_volume_bounded(...) -> AnalyticsResult<Vec<...>>
• Line ~385: pub fn get_top_chains_by_volume(...) -> AnalyticsResult<Vec<...>>
• Both functions return Result types
• No .unwrap() in sorting code

Specific Test:

# Verify no unwrap in sorting loops
sed -n '340,380p' contracts/teachlink/src/analytics.rs | grep "unwrap"

Expected: No unwrap found

Step 4.2: Access Control Module

grep -n "check_role" contracts/teachlink/src/access_control.rs

Expected Result:

• Line ~36: pub fn check_role(...) -> AccessControlResult<()>
• Returns Result instead of void
• Error returned: Err(AccessControlError::MissingRole)
• No panic!() call

Verification:

sed -n '36,42p' contracts/teachlink/src/access_control.rs | grep -c "panic"

Expected: 0 panics found

Step 4.3: Reputation Module

# Check all three functions return Result
grep -E "pub fn (update_participation|update_course_progress|rate_contribution)" \
  contracts/teachlink/src/reputation.rs

Expected Result: All three functions signature should show:

• -> ReputationResult<()>

Verify no assert!:

grep -c "assert!" contracts/teachlink/src/reputation.rs

Expected: Should be 0 or only in test code

Step 4.4: Bridge Module

# Check getter functions
grep -A2 "pub fn get_token\|pub fn get_admin" contracts/teachlink/src/bridge.rs

Expected Result:

• Both return Result<Address, BridgeError>
• No .unwrap() calls
• Proper error conversion: .map_err(|_| BridgeError::StorageError)

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Part 5: Test Compilation and Execution

Step 5.1: Run Unit Tests

cargo test --lib -p teachlink-contract

Expected Result:

• All tests pass
• No test panics
• Error handling tests compile

Step 5.2: Run Integration Tests

cargo test --test error_handling_integration -p teachlink-contract

Expected Result:

• Test file compiles without errors
• All integration tests pass
• Compilation successful (dummy test passes)

Step 5.3: Check Test Output for Error Cases

cargo test --lib -- --nocapture 2>&1 | grep -i "error\|result"

Expected Result:

• Error handling is properly tested
• No unexpected panics in test output
• Result types are properly used in tests

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Part 6: Code Review Verification

Step 6.1: Analytics Refactor Review

File: contracts/teachlink/src/analytics.rs

Checklist:

• Imports include: use crate::errors::{AnalyticsError, AnalyticsResult, ...}
• get_top_chains_by_volume_bounded returns AnalyticsResult<Vec<(u32, i128)>>
• get_top_chains_by_volume returns AnalyticsResult<Vec<(u32, i128)>>
• Sorting code uses .ok_or(AnalyticsError::InvalidIndex)? instead of .unwrap()
• All Vec access properly handles errors

Step 6.2: Access Control Refactor Review

File: contracts/teachlink/src/access_control.rs

Checklist:

• Imports include: use crate::errors::{AccessControlError, AccessControlResult, ...}
• check_role function returns AccessControlResult<()>
• No panic!() macro in check_role
• grant_role and revoke_role convert errors: .map_err(|_| BridgeError::Unauthorized)?
• All authorization checks return Results

Step 6.3: Reputation Refactor Review

File: contracts/teachlink/src/reputation.rs

Checklist:

• Imports include: use crate::errors::{ReputationError, ReputationResult}
• update_participation returns ReputationResult<()>
• update_course_progress returns ReputationResult<()>
• rate_contribution returns ReputationResult<()>
• Invalid rating check: if rating > 5 { return Err(ReputationError::InvalidRating) }
• No assert!() macro in production code

Step 6.4: Bridge Refactor Review

File: contracts/teachlink/src/bridge.rs

Checklist:

• get_token returns Result<Address, BridgeError>
• get_admin returns Result<Address, BridgeError>
• No .unwrap() on config getters
• Fee recipient error handling: .map_err(|_| BridgeError::StorageError)?
• All repository operations properly handle errors

Step 6.5: Errors Module Review

File: contracts/teachlink/src/errors.rs

Checklist:

• AccessControlError enum defined with codes 500-505
• AnalyticsError enum defined with codes 510-514
• ReputationError enum defined with codes 520-525
• TokenizationError enum defined with codes 530-536
• AdvancedReputationError enum defined with codes 540-544
• All Result type aliases defined
• Error codes don't overlap
• All errors are contracterror decorated

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Part 7: Documentation Verification

Step 7.1: Error Handling Guide

ls -la contracts/teachlink/ERROR_HANDLING_GUIDE.md

Expected Result: File exists with:

• Overview section
• Principles section
• Error hierarchy defined
• Implementation patterns documented
• Checklist for implementation
• Testing guidelines

Step 7.2: Error Handling Tests

ls -la contracts/teachlink/tests/error_handling_integration.rs

Expected Result: File exists with:

• Test module defined
• Test cases for each refactored module
• Manual testing checklist
• Compilation test

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Part 8: Performance Verification (Optional)

Step 8.1: Build Size Comparison

# Check WASM size (should not significantly increase)
ls -lh target/wasm32-unknown-unknown/release/teachlink_contract.wasm

Expected Result: WASM size is reasonable and not significantly increased

Step 8.2: Gas Estimation

# If available, run gas benchmark
./scripts/check_performance.sh

Expected Result: No significant gas cost increase from error handling

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Part 9: Final Validation Checklist

Item	Status	Evidence
Build succeeds without errors	[ ]	cargo build --release output
No unwrap() in production code	[ ]	grep results
No panic!/assert! in production code	[ ]	grep results
All error enums defined	[ ]	errors.rs review
All Result types defined	[ ]	errors.rs review
Analytics functions return Result	[ ]	function signatures
Access Control functions return Result	[ ]	function signatures
Reputation functions return Result	[ ]	function signatures
Bridge functions return Result	[ ]	function signatures
Tests compile and pass	[ ]	cargo test output
Error codes are unique	[ ]	manual review
Documentation updated	[ ]	files exist
No silent failures	[ ]	code review

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Troubleshooting

Issue: Build fails with "unwrap cannot find associated function"

Solution: Ensure all Result types are properly imported:

use crate::errors::{ErrorType, ErrorTypeResult};

Issue: Tests fail with "expected Result, found T"

Solution: Update test code to handle Result types:

// Before
let result = function();

// After
let result = function()?;  // or
match function() {
    Ok(v) => { /* use v */ },
    Err(e) => { /* handle e */ },
}

Issue: Compiler warning "unused Result"

Solution: Either use the Result or explicitly ignore it:

// Discouraged
function()?;  // unused result

// Encouraged
let _ = function()?;  // explicitly ignored
function()?;  // used via ? operator in function returning Result

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Success Criteria

The assignment is successfully completed when:

1. ✓ All builds pass - cargo build --release completes without errors
2. ✓ No panics - Production code contains no panic!/assert! macros
3. ✓ No silent failures - All fallible operations return Result types
4. ✓ Specific errors - Each error type has its own variant with meaningful code
5. ✓ Proper propagation - ? operator used for error propagation
6. ✓ Tests pass - All unit and integration tests pass
7. ✓ Documentation complete - Error handling guide and tests provided

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Next Steps After Verification

1. Run full test suite: ./scripts/test.sh
2. Check linting: ./scripts/lint.sh
3. Deploy to testnet: ./scripts/deploy-testnet.sh
4. Verify on-chain behavior matches expected error handling

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Questions or Issues?

Refer to:

• ERROR_HANDLING_GUIDE.md - Implementation patterns
• tests/error_handling_integration.rs - Test cases
• src/errors.rs - Error definitions