psalm/psalm.xml

<?xml version="1.0"?>
<psalm
    name="Psalm for Psalm"
    stopOnFirstError="false"
    useDocblockTypes="true"
    totallyTyped="true"
    strictBinaryOperands="false"
>
    <projectFiles>
        <directory name="src" />
        <directory name="tests" />
    </projectFiles>

    <issueHandler>
        <NullOperand errorLevel="suppress" />

        <MissingReturnType>
            <ignoreFiles>
                <directory name="tests" />
            </ignoreFiles>
        </MissingReturnType>

        <MissingPropertyType>
            <ignoreFiles>
                <directory name="tests" />
            </ignoreFiles>
        </MissingPropertyType>

        <MixedArgument>
            <ignoreFiles>
                <directory name="tests" />
            </ignoreFiles>
        </MixedArgument>

        <MixedOperand>
            <ignoreFiles>
                <directory name="tests" />
            </ignoreFiles>
        </MixedOperand>

        <MixedPropertyFetch>
            <ignoreFiles>
                <directory name="tests" />
            </ignoreFiles>
        </MixedPropertyFetch>

        <NoInterfaceProperties>
            <ignoreFiles>
                <directory name="tests" />
            </ignoreFiles>
        </NoInterfaceProperties>

        <NullArrayAccess>
            <ignoreFiles>
                <directory name="tests" />
            </ignoreFiles>
        </NullArrayAccess>

        <NullPropertyFetch>
            <ignoreFiles>
                <directory name="tests" />
            </ignoreFiles>
        </NullPropertyFetch>

        <NullArgument>
            <ignoreFiles>
                <directory name="tests" />
            </ignoreFiles>
        </NullArgument>
    </issueHandler>
</psalm>