TSLint rule to avoid accidental `fdescribe` and `fit` calls in test code

noFdescribeOrFitRule.ts

// Dependencies:
import { tsquery } from '@phenomnomnominal/tsquery';
import { Fix, Replacement, RuleFailure, Rules } from 'tslint';
import { SourceFile } from 'typescript';

// Constants:
const FDESCRIBE_FIT_QUERY = 'CallExpression > Identifier[name=/^f(describe|it)$/]';

const FAILURE_MESSAGE = (filter: string) => `

    Remember to remove "${filter}" once you have finished working on tests.

`;

export class Rule extends Rules.AbstractRule {
    public apply (sourceFile: SourceFile): Array<RuleFailure> {

        const options = this.getOptions();
        const [fileFilter] = options.ruleArguments;
        if (fileFilter && !sourceFile.fileName.includes(fileFilter)) {
            return [];
        }

        return tsquery(sourceFile, FDESCRIBE_FIT_QUERY).map(result => {
            const replacement = new Replacement(result.getStart(), result.getWidth(), result.name.replace(/^f/, ''));
            return new RuleFailure(result.getSourceFile(), result.getStart(), result.getEnd(), FAILURE_MESSAGE(result.name as string), this.ruleName, replacement);
        });
    }
}