I need help writing a test class for the below apex class using a mock test :
 
Apex Class First

public with sharing class B2B_wordlineCreateHostedCheckout {
    
    @AuraEnabled
    public static String createHostedCheckout(String shopName, String issuerId) {
        try {
            String shopNameTemp = shopName;
            String newShopName = shopName.substring(1);
            Http httpCall = new Http();
            HttpRequest httpRequest = new HttpRequest();
            Map<String, B2B_Wordline_Config__mdt> shopDetailsMap = B2B_Wordline_Config__mdt.getAll();
            system.debug('shopDetailsMap11'+shopDetailsMap);
            String apiKey = shopDetailsMap.get(newShopName).apiKey__c;
            String apiSecret = shopDetailsMap.get(newShopName).apiSecret__c;
            String pspId = shopDetailsMap.get(newShopName).pspId__c;
            String hostName = shopDetailsMap.get(newShopName).hostName__c;
            String webStoreName = shopDetailsMap.get(newShopName).webStoreName__c;
            String requestMethod = 'POST';
            String contentType = 'application/json';
            String uriResource = '/hostedcheckouts';
            String endpointURL = '/v2/' + pspId + uriResource;
            String responseString = '';
            String UserId = UserInfo.getUserId();
            System.debug('Community User Id: ' + UserId);
            System.debug('webStoreName+++28'+webStoreName);
            
            // Retrieve the latest cart for the user
            WebCart cart = [SELECT Id, GrandTotalAmount, CurrencyIsoCode FROM WebCart 
                            WHERE Owner.id = :UserId
                            AND Status = 'Checkout'
                            AND WebStore.Name = :webStoreName 
                            ORDER BY LastModifiedDate DESC LIMIT 1];
            System.debug('cart+++28'+cart);
            if (cart == null) {
                throw new AuraHandledException('No cart found for the user.');
            }
            String baseUrl = URL.getSalesforceBaseUrl().toExternalForm();
            Decimal grandTotalAmount = cart.GrandTotalAmount;
            String currencyIsoCode = cart.CurrencyIsoCode;
            String uriEndPoint = '/checkout';
            String checkoutURL = baseUrl + shopNameTemp + uriEndPoint ;
            System.debug('checkoutURL+++41'+checkoutURL);
            String jsonText = '{"order":{"amountOfMoney":{"amount":' + grandTotalAmount + ',"currencyCode":"' + currencyIsoCode + '"}},';
            jsonText += '"hostedCheckoutSpecificInput":{"returnUrl":"' + checkoutURL + '"}';
            if (issuerId != null) {
                jsonText += ',"redirectPaymentMethodSpecificInput":{"paymentProductId":"809","paymentProduct809SpecificInput":{"issuerId":"' + issuerId + '"}}';
            }
            jsonText += '}';
            System.debug('jsonText+++41'+jsonText);
            Map<String, Object> jsonData = (Map<String, Object>) JSON.deserializeUntyped(jsonText);
            String requestBodyJson = JSON.serialize(jsonData);
            System.debug('requestBodyJson+++41'+requestBodyJson);
            httpRequest = B2B_worldlineUtility.makeHttpRequest(endpointURL, requestMethod, contentType, apiKey, apiSecret, requestBodyJson, hostname);
            System.debug('httpRequest+++41'+httpRequest);
            HttpResponse httpResponse = httpCall.send(httpRequest);
            System.debug('httpResponse+++41'+httpResponse);
            return httpResponse.getBody();
        } catch (Exception ex) {
            throw new AuraHandledException('An error occurred: ' + ex.getMessage());
        }
    }

    @AuraEnabled
    public static string getProductDirectory(String shopName) {
        try {
            String currencyISOCode ;
            String userId = UserInfo.getUserId();
            User currentUser = [SELECT Id, CurrencyIsoCode FROM User WHERE Id = :userId LIMIT 1];
            
            if (currentUser != null) {
                currencyISOCode = currentUser.CurrencyIsoCode;
                System.debug('currencyISOCode: ' + currencyISOCode);
            } else {
                throw new AuraHandledException('Currency ISO Code Is Not available');
            }
            
            String newShopName = shopName.substring(1);
            List<String> strings = newShopName.split(';');
            for (String eachString : strings) {
                List<String> nameSplits = eachString.split('/');
                newShopName = nameSplits.get(0).removeStart(' ');
            }
            Http httpCall = new Http();
            HttpRequest httpRequest = new HttpRequest();
            Map<String, B2B_Wordline_Config__mdt> shopDetailsMap = B2B_Wordline_Config__mdt.getAll();
            B2B_Wordline_Config__mdt shopConfig = shopDetailsMap.get(newShopName);
            
            if (shopConfig == null) {
                throw new AuraHandledException('Shop configuration not found for shopName: ' + newShopName);
            }
            
            String apiKey = shopConfig.apiKey__c;
            String apiSecret = shopConfig.apiSecret__c;
            String pspId = shopConfig.pspId__c;
            String hostName = shopConfig.hostName__c;
            String webStoreName = shopConfig.webStoreName__c;
            String countryCode = shopConfig.Country_Code__c;
            String requestMethod = 'GET';
            String contentType = 'application/json';
            String uriResource = '/products/809/directory?countryCode=' + countryCode + '&currencyCode=' + currencyISOCode;
            String endpointURL = '/v2/' + pspId + uriResource;
            String responseString = '';
            httpRequest = B2B_worldlineUtility.makeHttpRequest(endpointURL, requestMethod, contentType, apiKey, apiSecret, null, hostname);
            HttpResponse httpResponse = httpCall.send(httpRequest);
            System.debug('httpResponse.getBody(): ' + httpResponse.getBody());
            return String.valueOf(httpResponse.getBody());
        } catch (Exception ex) {
            throw new AuraHandledException('An error occurred: ' + ex.getMessage());
        }
    }

    @AuraEnabled
    public static String checkForHostedCheckout(String shopName,String hostedCheckoutId) {
        // https://payment.preprod.direct.worldline-solutions.com/v2/{merchantId}/hostedcheckouts/{hostedCheckoutId}
        system.debug('hostedCheckoutId: ' +hostedCheckoutId);
        String newShopName = shopName.substring(1);
        Http httpCall = new Http();
        HttpRequest httpRequest = new HttpRequest();
        Map<String, B2B_Wordline_Config__mdt> shopDetailsMap = B2B_Wordline_Config__mdt.getAll();
        String apiKey = shopDetailsMap.get(newShopName).apiKey__c;
        String apiSecret = shopDetailsMap.get(newShopName).apiSecret__c;
        String pspId = shopDetailsMap.get(newShopName).pspId__c;
        String hostName = shopDetailsMap.get(newShopName).hostName__c;
        String webStoreName = shopDetailsMap.get(newShopName).webStoreName__c;
        String requestMethod = 'GET';
        String contentType = 'application/json';
        String uriResource = '/hostedcheckouts/' + hostedCheckoutId;
        String endpointURL = '/v2/' + pspId + uriResource;
        String responseString = '';
        httpRequest = B2B_worldlineUtility.makeHttpRequest(endpointURL, requestMethod, contentType, apiKey, apiSecret, null, hostname);
        HttpResponse httpResponse = httpCall.send(httpRequest);
        return httpResponse.getBody();
    }    
}

Apex Class Second 

public class B2B_worldlineUtility {
    public static httpRequest makeHttpRequest(String endpointUrl, String requestMethod, String contentType, String apiKey, String apiSecret, String requestBody, String hostname) {
        HttpRequest httpRequest = new HttpRequest();
        httpRequest.setEndpoint('https://' + hostname + endpointURL);
        httpRequest.setMethod(requestMethod);
        if (requestBody != null) {
            httpRequest.setBody(requestBody);
        }
        httpRequest.setHeader('Content-Type', contentType);
        httpRequest.setHeader('Authorization', 'GCS v1HMAC:' + apiKey + ':' + generateSignatureForGET(requestMethod, contentType, endpointUrl, apiSecret));
        httpRequest.setHeader('Host', hostname);
        httpRequest.setHeader('Date', getFormattedCurrentTime());
        httpRequest.setHeader('Accept-Encoding', 'gzip, deflate, br');
        httpRequest.setHeader('Connection', 'keep-alive');
        httpRequest.setHeader('Accept', 'application/json');
        return httpRequest;
    }

    public static String generateSignatureForGET(String requestMethod, String contentType, String endpointUrl, String apiSecret) {
        if (requestMethod == 'GET' || requestMethod == 'DELETE') {
            contentType = '';
        }
        String stringToHash = requestMethod + '\n' + contentType + '\n' + getFormattedCurrentTime() + '\n' + endpointUrl + '\n';
        Blob hmacSHA256Blob = Crypto.generateMac('HmacSHA256', Blob.valueOf(stringToHash), Blob.valueOf(apiSecret));
        return EncodingUtil.base64Encode(hmacSHA256Blob);
    }

    public static String getFormattedCurrentTime() {
        return Datetime.now().format('EEE, dd MMM yyyy HH:mm:ss') + ' GMT';
    }
}