How to check whether a string contains a substring in Mule?

I want to use the Assert Equals component to find if a string exists in my payload. I give an example:

Txt|Name=ST CLAUD|Country=SPAIN|Txtld=45

I want to search if the payload contains the string "SPAIN" Is there a mule expression MEL to do that?

Thank you in advance

you should use Assert True instead of Assert Equals and use the contains method defined in java.lang.Stirng (assumed payload is of type String!).

example:

<munit:test name="dataweaveTest" description="MUnit Test">
    <munit:set payload="Txt|Name=ST CLAUD|Country=SPAIN|Txtld=45" doc:name="Set Message"/>
    <munit:assert-true doc:name="Assert True"
        condition="#[payload.contains('SPAINA')]" />
</munit:test>

here is what it looks like in AnypointStudio: