Backtesting

The debugger is a built-in tool to help you debug coding errors while backtesting. The debugger enables you to slow down the code execution, step through the program line-by-line, and inspect the variables to understand the internal state of the program.

Breakpoints are lines in your algorithm where execution pauses. You need at least one breakpoint in your code files to start the debugger. Open a project to start adjusting its breakpoints.

Add Breakpoints

Click to the left of a line number to add a breakpoint on that line.

Edit Breakpoint Conditions

Follow these steps to customize what happens when a breakpoint is hit:

1. Right-click the breakpoint and then click Edit Breakpoint....
2. Click one of the options in the following table:

Enable and Disable Breakpoints

To enable a breakpoint, right-click it and then click Enable Breakpoint.

To disable a breakpoint, right-click it and then click Disable Breakpoint.

Follow these steps to enable and disable all breakpoints:

1. In the right navigation menu, click the Run and Debug icon.
2. In the Run and Debug panel, hover over the Breakpoints section and then click the Toggle Active Breakpoints icon.

Remove Breakpoints

To remove a breakpoint, right-click it and then click Remove Breakpoint.

Follow these steps to remove all breakpoints:

1. In the right navigation menu, click the Run and Debug icon.
2. In the Run and Debug panel, hover over the Breakpoints section and then click the Remove All Breakpoints icon.

Follow these steps to launch the debugger:

1. Open the project you want to debug.
2. In your project's code files, add at least one breakpoint.
3. Click the Debug icon.

If the Run and Debug panel is not open, it opens when the first breakpoint is hit.

After you launch the debugger, you can use the following buttons to control it:

Button	Name	Default Keyboard Shortcut	Description
	Continue		Continue execution until the next breakpoint
	Step Over	Alt+F10	Step to the next line of code in the current or parent scope
	Step Into	Alt+F11	Step into the definition of the function call on the current line
	Restart	Shift+F11	Restart the debugger
	Disconnect	Shift+F5	Exit the debugger

After you launch the debugger, you can inspect the state of your algorithm as it executes each line of code. You can inspect local variables or custom expressions. The values of variables in your algorithm are formatted in the IDE to improve readability. For example, if you inspect a variable that references a DataFrame, the debugger represents the variable value as the following:

Local Variables

The Variables section of the Run and Debug panel shows the local variables at the current breakpoint. If a variable in the panel is an object, click it to see its members. The panel updates as the algorithm runs.

Follow these steps to update the value of a variable:

1. In the Run and Debug panel, right-click a variable and then click Set Value.
2. Enter the new value and then press Enter.

Custom Expressions

The Watch section of the Run and Debug panel shows any custom expressions you add. For example, you can add an expression to show the current date in the backtest.

Follow these steps to add a custom expression:

1. Hover over the Watch section and then click the plus icon that appears.
2. Enter an expression and then press Enter.