Problem with field validation on a visualforce page with a controller

Question

I have a custom object with a visualforce page, 2 controllers, and a custom button. The issue is if I use the "Save & New" custom button my validation for a field won't show the error on my page. However if I use the standard Save button it will. The "Save & New" WILL the exception if I don't fill out a required field.

Validation:

Rule Name No_Test_Validation
Active Checked

Error Condition Formula AND(ISPICKVAL(Result__c ,"No Test"), ISBLANK(Testing_Notes__c))

Error Message WARNING! If test result is "No Test" you need to enter Testing Notes

Visualforce Page:

<apex:page standardController="Test__c" showheader="True"><apex:pagemessages / ><apex:form >
<apex:sectionHeader title="{!$ObjectType.Test__c.label}" subtitle="{!Test__c.name}"/>
    <apex:pageBlock title="{!$ObjectType.Test__c.label} Detail" >

        <apex:pageBlockButtons >   
                    <apex:commandButton action="{!save}" value="Save"/>
                    <apex:commandButton action="{!cancel}" value="Cancel"/>   
           </apex:pageBlockButtons>

        <apex:pageBlockSection title="Edit Test Info" showHeader="true" columns="2">

                <apex:pageBlockSectionItem >
                    <apex:outputLabel value="Test Number" />
                    <apex:outputfield value="{!Test__c.Test_Number__c}" />
                </apex:pageBlockSectionItem>

                <apex:pageBlockSectionItem >
                    <apex:outputLabel value="Inspection Id" />
                    <apex:outputfield value="{!Test__c.Inspection__c}" />
                </apex:pageBlockSectionItem>

                <apex:pageBlockSectionItem >
                </apex:pageBlockSectionItem>  

                <apex:pageBlockSectionItem >
                    <apex:outputLabel value="Type of Test" />
                    <apex:inputfield value="{!Test__c.Type_of_Test__c}" />
                </apex:pageBlockSectionItem>

                <apex:pageBlockSectionItem >
                    <apex:outputLabel value="Test Value" />
                    <apex:inputField value="{!Test__c.Test_Value__c}" />
                </apex:pageBlockSectionItem>

                <apex:pageBlockSectionItem >
                </apex:pageBlockSectionItem>  

                <apex:pageBlockSectionItem >
                    <apex:outputLabel value="Result" />
                    <apex:inputField value="{!Test__c.Result__c}" />
                </apex:pageBlockSectionItem>

                <apex:pageBlockSectionItem >
                </apex:pageBlockSectionItem> 

                <apex:pageBlockSectionItem >
                    <apex:outputLabel value="Test Unit Id #" />
                    <apex:inputField value="{!Test__c.Test_Unit_ID__c}" />
                </apex:pageBlockSectionItem>  

                <apex:pageBlockSectionItem >
                    <apex:outputLabel value="Testing Notes" />
                    <apex:inputField value="{!Test__c.Testing_Notes__c}" />
                </apex:pageBlockSectionItem>



        </apex:pageBlockSection>

        <apex:pageBlockSection showHeader="false" columns="2">
            <apex:outputField value="{!Test__c.CreatedById}"/>
            <apex:outputField value="{!Test__c.LastModifiedById}"/>
        </apex:pageBlockSection>

    </apex:pageBlock> 
    </apex:form>  

Controller:

public with sharing class ButtonSaveAndNew {
    private Test__c foo;
    private ApexPages.StandardController sController;
    private String queryString;

    public ButtonSaveAndNew (ApexPages.StandardController controller) {
        sController = controller;
        foo = (Test__c)controller.getRecord();

        // Keep track of any inbound query string parameters so they can be passed along when creating a new record
        List<string> pageUrl = ApexPages.currentPage().getUrl().split('\\?');
        queryString = pageUrl[1];
    }

    public PageReference saveAndNew() {


        try {
            // Save the current sObject
            sController.save();
            // Get the Meta Data for Foo__c
            Schema.DescribeSObjectResult describeResult = sController.getRecord().getSObjectType().getDescribe();
            // Create PageReference for creating a new sObject and add any inbound query string parameters.
            PageReference pr = new PageReference('/' + describeResult.getKeyPrefix() + '/e?' + queryString);
            // Don't redirect with the viewstate of the current record.
            pr.setRedirect(true);
            return pr;
        } catch(Exception e) {
            // Don't redirect if something goes wrong. May be a validation or trigger issue on save.
            ApexPages.addMessages(e);
            return null;
        }
    }
}

Second Controller

public class getTotalTests {
    ApexPages.StandardController sController;

    public getTotalTests(ApexPages.StandardController controller) {
        sController = controller;
        system.debug('TotalTestLoad');
    }

    public Integer getTests(){
        Test__c record = (Test__c)scontroller.getRecord();
        List<Test__c> t = [SELECT Id, Inspection__c
                                  FROM Test__c 
                                  WHERE Inspection__c = :record.Inspection__c];
            Integer numb = t.size() +1;
            return numb;
    }
}

Answer 1

StandardController#save does not throw an exception; instead, it acts more like a DML operation with allOrNone set to false (i.e. allows partial saves). It simply returns null on a validation error. You could write your code as follows:

if(sController.save() != null) { // Saved okay
    // Get the Meta Data for Foo__c
    Schema.DescribeSObjectResult describeResult = sController.getRecord().getSObjectType().getDescribe();
    // Create PageReference for creating a new sObject and add any inbound query string parameters.
    PageReference pr = new PageReference('/' + describeResult.getKeyPrefix() + '/e?' + queryString);
    // Don't redirect with the viewstate of the current record.
    return pr.setRedirect(true);
}
return null;