Error in apex test logs: common.apex.runtime.impl.ExecutionException: List has no rows for assignment to SObject"

Question

Here is what i tried. I think the problem is somewhere in the test class when i create the apex test controller and i want to link the record of the controller to the solution that i created in the test class.

This is the error that i found in logs: "common.apex.runtime.impl.ExecutionException: List has no rows for assignment to SObject"|0x4888dd3c

apex class:

public with sharing class SolutionWrapper {
public ApexPages.StandardSetController controller;
public Opportunity opp{get; set;}
public Solutions__c oppId{get; set;}
public Solutions__c sol{get; set;}
public Solutions__c solution{get; set;}
public Account acc{get; set;}

public SolutionWrapper(ApexPages.StandardSetController controller) {
    try{
        solution = new Solutions__c();
        solution = (Solutions__c)controller.getRecord();
        if(solution.Id != null){
            oppId = [SELECT id, Solutions__c.Opportunity__c 
                FROM Solutions__c
            WHERE id =: solution.Id
            LIMIT 1];

            opp = [Select id,Name, AccountId, CurrencyIsoCode  from 
                     Opportunity where id =: oppId.Opportunity__c  LIMIT:1];
        }

        if(opp.id !=null){
            sol = [SELECT id,Name, Mail_Merge_Id__c,Solution_Country__c, Solutions__c.Opportunity__c 
        FROM Solutions__c
        WHERE Solutions__c.Opportunity__c =: opp.id
        LIMIT 1];
             acc = [Select id,Name,Country__c from 
                     Account where id=:opp.AccountId LIMIT: 1];
        }


    }
    catch(Exception e){
        ApexPages.addMessage(new ApexPages.message(ApexPages.Severity.ERROR,e.getMessage()));
    }

}

}

Here is my test class

apex test class:

@isTest 
public class SolutionWrapperTest {

     static testMethod void testMethodOpp(){
         Account acc = new Account(Name='test', Country__c='test'); 
          insert acc; 
         Opportunity opp = new Opportunity(Name='test', AccountId=acc.id, CurrencyIsoCode='GBP', StageName = 'Good',
          CloseDate =  date.today());
         insert opp;
         Solutions__c sol = new Solutions__c( Opportunity__c= opp.id, CurrencyIsoCode='GBP');       
           insert sol;          

         List<Solutions__c> listSol = new List<Solutions__c>();
         listSol.add(sol);
         PageReference pageRef = Page.NewVisualForcePage;
         Test.setCurrentPage(pageRef); 

        Test.startTest();
         ApexPages.StandardSetController stdController = new ApexPages.StandardSetController(listSol);
         SolutionWrapper testSolution = new SolutionWrapper(stdController);
        Test.stopTest();

        }


}

Answer 1

Solution id is different from the one that i inserted in the test class. I inserted a dummy value (eq 'test') on a field like Currency. After that i selected from the db based on Currency instead of id.