Introduction

Control flow structures allow test automation scripts to make decisions, repeat tasks, and handle different test cases dynamically. This module covers conditional statements, loops, and type-safe assertions to create robust TypeScript test scripts.

Lesson 1: Conditional Statements – if, else if, else with Type Guards

Concept:
Conditional statements enable automated tests to branch logic based on specific conditions.

Key Topics:

  • Basic if-else Statements: Controlling test execution based on conditions.
  • Multiple Conditions: Using else if for handling various test scenarios.
  • Type Guards: Ensuring type safety within conditionals.

Example:

let testStatus: string | null = "Passed";
if (testStatus === "Passed") {
    console.log("Test succeeded.");
} else if (testStatus === "Failed") {
    console.log("Test failed. Needs debugging.");
} else {
    console.log("Unknown test status.");
}

Pro Tip: Use TypeScript’s typeof or instanceof for type guards in complex conditionals.

Lesson 2: Mastering Loops – for, while, for...of, and forEach

Concept:
Loops automate repetitive tasks such as iterating through test cases or dataset validations.

Key Topics:

  • for Loop: Iterating a set number of times.
  • while Loop: Running until a condition is false.
  • for...of Loop: Simplified iteration over arrays.
  • forEach Method: Functional iteration over collections.

Example:

let testCases: string[] = ["Login", "Signup", "Checkout"];
for (let test of testCases) {
    console.log(`Running ${test} test...`);
}

Pro Tip: Use forEach() for cleaner, functional-style array iteration in test automation scripts.

Lesson 3: Boolean Logic and Comparison Operators – Building Type-Safe Assertions

Concept:
Boolean logic allows test scripts to evaluate conditions and execute assertions.

Key Topics:

  • Comparison Operators: ===, !==, >, <, >=, <=
  • Logical Operators: &&, ||, ! for complex conditions.
  • Type-Safe Assertions: Validating expected vs. actual test results.

Example:

let expected: string = "Success";
let actual: string = "Success";
console.assert(expected === actual, "Test result mismatch");

Pro Tip: Use strict equality (===) to avoid unintended type coercion in assertions.

Conclusion

This module covered JavaScript control flow structures, helping to write dynamic and efficient test automation scripts.

Key Takeaways:

  • Conditional statements help automate decision-making in test execution.
  • Loops simplify repetitive tasks, making tests more scalable.
  • Boolean logic and assertions ensure expected test results.

What’s Next?
In the next module, we will explore Data Structures in TypeScript: Organizing Test Data with Strong Typing, covering arrays, objects, tuples, and enums to store and manage test data efficiently.

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