Method return_error

datafusion/datasource/src/morsel/mocks.rs:400–405

Adds one planning step that fails during CPU planning.

(mut self, message: impl Into<String>)

    /// Adds one planning step that fails during CPU planning.
    pub(crate) fn return_error(mut self, message: impl Into<String>) -> Self {
        self.steps.push(PlannerStep::Error {
            error: MockError(message.into()),
        });
        self
    }

    /// Finalizes the configured mock planner.
    pub(crate) fn build(self) -> MockPlanner {