Debugging and Testing 🔍

Debugging Techniques

Visual Debugging

//@version=5
indicator("Visual Debug", overlay=true)

// Add visual markers for debugging
debugPoint(message) =>
    if barstate.islast
        label.new(bar_index, high, message,
            color=color.blue,
            textcolor=color.white,
            style=label.style_label_down)

// Example usage
sma = ta.sma(close, 14)
if ta.crossover(close, sma)
    debugPoint("Crossover: " + str.tostring(close))

Console Logging

//@version=5
indicator("Debug Logging")

// Create debug log
var string[] debugLog = array.new_string(0)

log(message) =>
    if array.size(debugLog) > 100
        array.shift(debugLog)
    array.push(debugLog, 
        str.tostring(bar_index) + ": " + message)

// Example usage
log("SMA: " + str.tostring(ta.sma(close, 14)))
log("RSI: " + str.tostring(ta.rsi(close, 14)))

Testing Framework

Unit Testing

//@version=5
indicator("Unit Tests")

// Test case structure
type TestCase
    string name
    bool result
    string message

// Test runner
var TestCase[] tests = array.new<TestCase>(0)

runTest(name, condition, message) =>
    test = TestCase.new(name, condition, message)
    array.push(tests, test)
    condition

// Example tests
testSMA() =>
    sma = ta.sma(close, 14)
    runTest("SMA Test", 
        not na(sma),
        "SMA should not be NA")

testRSI() =>
    rsi = ta.rsi(close, 14)
    runTest("RSI Range", 
        rsi >= 0 and rsi <= 100,
        "RSI should be between 0 and 100")

Integration Testing

//@version=5
strategy("Integration Tests", overlay=true)

// Test complete strategy flow
testStrategyFlow() =>
    var int successfulTrades = 0
    var int failedTrades = 0

    // Entry conditions
    longCondition = ta.crossover(ta.sma(close, 14), ta.sma(close, 28))
    if longCondition
        strategy.entry("Long", strategy.long)
        
    // Exit conditions
    if strategy.position_size > 0
        if close < strategy.position_avg_price * 0.95  // Stop loss
            strategy.close("Long")
            failedTrades += 1
        else if close > strategy.position_avg_price * 1.05  // Take profit
            strategy.close("Long")
            successfulTrades += 1

    [successfulTrades, failedTrades]

Error Handling

Robust Error Checking

//@version=5
indicator("Error Handling")

// Custom error type
type Error
    string message
    string code
    int severity

// Error handling function
handleError(condition, message, code="ERR", severity=1) =>
    if condition
        error = Error.new(message, code, severity)
        array.push(errorLog, error)
        runtime.error(message)

// Example usage
price = request.security(syminfo.tickerid, "D", close)
handleError(na(price), "Failed to fetch price data", "DATA_ERR", 2)

Performance Testing

Load Testing

//@version=5
indicator("Load Test")

// Simulate heavy load
loadTest(iterations) =>
    var float[] results = array.new_float(0)
    startTime = timenow
    
    for i = 1 to iterations
        value = ta.sma(close, i)
        array.push(results, value)
    
    endTime = timenow
    endTime - startTime

// Run tests with different loads
light = loadTest(10)
medium = loadTest(50)
heavy = loadTest(100)

Regression Testing

Historical Validation

//@version=5
strategy("Regression Test")

// Track historical performance
var float[] returns = array.new_float(0)
var float[] drawdowns = array.new_float(0)

// Calculate metrics
calculateMetrics() =>
    if strategy.closedtrades > 0
        array.push(returns, strategy.netprofit)
        array.push(drawdowns, strategy.max_drawdown)

// Compare with baseline
compareBaseline() =>
    avgReturn = array.avg(returns)
    avgDrawdown = array.avg(drawdowns)
    baselineReturn = 0.05  // 5% baseline return
    baselineDrawdown = 0.10  // 10% baseline drawdown
    
    [avgReturn > baselineReturn, avgDrawdown < baselineDrawdown]

Monitoring Tools

Performance Metrics

//@version=5
indicator("Performance Monitor")

// Track key metrics
type Metrics
    float executionTime
    int memoryUsage
    int errorCount

// Monitor script performance
var Metrics metrics = Metrics.new(0.0, 0, 0)
startTime = timenow

// Your script logic here
result = ta.sma(close, 200)

// Update metrics
metrics.executionTime := timenow - startTime
metrics.memoryUsage := array.size(debugLog)

Testing Tips

• Write tests for critical components
• Use visual debugging for complex logic
• Implement comprehensive error handling
• Monitor performance metrics
• Maintain test coverage

Common Testing Mistakes

❌ Insufficient test cases ❌ Missing edge case tests ❌ Poor error handling ❌ Inadequate performance testing ❌ Lack of regression tests

Next Steps

Ready to learn about publishing and sharing your scripts? Move on to the next chapter! 🚀