HI SFdeveloper,Can anyone explain about test code coverage for 75% required.what is the common steps to follow test code coverage for every apex class .Here i have code with 0% Test code coverage so how can i do 75% .So kindly let me know ASAP.

APEX class:

public class theController {

   String searchText;

   List<Lead> results;

   public String getSearchText()

{
      return searchText;

   }

   public void setSearchText(String s) {

      searchText = s;

   System.debug('SEARCHTEXT:'+searcHText);
   }

   public List<Lead> getResults() {
      
     return results;
   }

   public PageReference doSearch() {
    

    results = (List<Lead>)[FIND :searchText RETURNING Lead(Name, Email, Phone)][0];
           
    return null;
   }
}

Visualforce page:

<apex:page controller="theController" showHeader="true">
<apex:messages />
   <apex:form >
      <apex:pageBlock mode="edit" id="block">
         <apex:pageBlockSection >
            <apex:pageBlockSectionItem >
               <apex:outputLabel for="searchText">Search Text</apex:outputLabel>
               <apex:panelGroup >
                  <apex:inputText id="searchText" value="{!searchText}"/>
                  <apex:commandButton value="Go!" action="{!doSearch}"
                                      rerender="block" status="status"/>
               </apex:panelGroup>
            </apex:pageBlockSectionItem>
        </apex:pageBlockSection>
        <apex:actionStatus id="status" startText="requesting..."/>
        <apex:pageBlockSection title="Results" id="results" columns="1">
           <apex:pageBlockTable value="{!results}" var="l"
                               rendered="{!NOT(ISNULL(results))}">
              <apex:column value="{!l.name}"/>
              <apex:column value="{!l.email}"/>
              <apex:column value="{!l.phone}"/>
           </apex:pageBlockTable>
        </apex:pageBlockSection>
      </apex:pageBlock>
   </apex:form>
</apex:page>