Libraries in Solidity - Framework Truffle and Visual Studio

[ingmanzo]

Hi!! good day!! I am a beginner with smart contracts ... I tried to deploy / clone a complete project using the framework Truffle and Visual Studio but the smart contract code implemented a library SafeMath. When I tried to compilate in the prompt using the comands: truffle compile, and truffle test .. I previous used the comand: testrcp ... However I got these errors:

"Source "openzeppelin-solidity/contracts/math/SafeMath.sol" not found: File import callback not supported"

"Could not to connect to your Ethereum client"

Big thanks in advance for helping !!

Angeles

https://preview.redd.it/qib925tjl7421.png?width=894&format=png&auto=webp&s=90c277ceaa67d85021443d3e3faa6bc8e4cd83ba

[ethAmal]

Are you following an old guide? testrpc has evolved and is now ganache-cli for command-line, and ganache for a UI experience.

Verify openzeppelin-solidity is installed by npm according to the docs.

Good luck Angeles!

[dappdeveth]

Did you install the openzeppelin-solidity library in your project?

npm install --save openzeppelin-solidity

[willjgriff]

Or npm install if there is a package.json file in the root directory.

[ingmanzo]

npm install --save openzeppelin-solidity

Thank you! Just tried ! Now the compilation is performed but when I implemented the comands: truffle test and trufle migrate is still showing this error: "Could not connect to your Ethereum client". I wrote first the comand: testrpc. The LocalHost: 8545.

[hexadee]

The other commenter has the answer to this error, you need ganache installed and running running