Gas usage testing in Blockchain / Solidity - Step-by-Step Execution

Concept Flow - Gas usage testing

Write smart contract function

↓

Deploy contract to test network

↓

Call function with test inputs

↓

Measure gas used by transaction

↓

Analyze gas usage

↓

Optimize code if needed

↓

Repeat testing

This flow shows how to write, deploy, call, measure, and optimize gas usage in smart contracts.

Execution Sample

Blockchain / Solidity

pragma solidity ^0.8.0;

contract GasTest {
    uint public count;
    function increment() public {
        count += 1;
    }
}

A simple contract with a function that increments a counter, used to test gas cost of calling increment.

Execution Table

Step	Action	Gas Used (approx.)	State Change	Notes
1	Deploy contract	1500000	count = 0	Initial deployment cost
2	Call increment()	2300	count = 1	First increment call
3	Call increment()	2300	count = 2	Second increment call
4	Call increment()	2300	count = 3	Third increment call
5	Stop testing	-	-	No more calls

💡 Testing stops after desired number of calls to measure gas usage.

Variable Tracker

Variable	Start	After 1	After 2	After 3
count	0	1	2	3

Key Moments - 2 Insights

Why does the gas used for deployment differ from gas used for function calls?

Deployment includes creating the contract on the blockchain, which costs more gas (see Step 1 in execution_table), while function calls only execute code and update state.

Why is gas usage roughly the same for each increment call?

Each increment call does the same simple operation (count += 1), so gas used is consistent (see Steps 2-4).

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of 'count' after Step 3?

A 2

B 1

C 3

D 0

💡 Hint

Check the 'State Change' column in row for Step 3.

At which step does the contract get deployed?

A Step 2

B Step 1

C Step 3

D Step 4

💡 Hint

Look for the action 'Deploy contract' in the execution_table.

If the increment function did more complex calculations, how would gas usage change?

A Gas used would decrease

B Gas used would stay the same

C Gas used would increase

D Gas used would be zero

💡 Hint

More operations in a function increase gas cost; see gas used in Steps 2-4.

Concept Snapshot

Gas usage testing steps:
1. Write and deploy contract
2. Call functions with test inputs
3. Measure gas used per call
4. Analyze and optimize
Gas cost depends on code complexity and state changes.

Full Transcript

Gas usage testing in blockchain means checking how much gas a smart contract function uses when called. First, you write a contract and deploy it to a test network. Deployment costs gas because it stores the contract on the blockchain. Then, you call the function you want to test, like incrementing a number. Each call uses gas depending on what the function does. You record gas used and state changes after each call. If gas is too high, you can optimize your code and test again. This helps save money when using real networks.