sql/test/parser.test.ts

/* tslint:disable:no-unused-expression */
import { expect } from "chai";

import * as AST from "../src/ast";
import { isError } from "../src/error";
import Lexer from "../src/lexer";
import Parser from "../src/parser";

const parse = (source: string): AST.Statement[] => {
  const tokens = new Lexer(source).scan();
  if (isError(tokens)) {
    throw tokens.message;
  } else {
    const tree = new Parser(tokens).parse();
    if (isError(tree)) {
      throw tree.message;
    }
    return tree;
  }
};

describe("Parser", () => {
  it("should parse a number selection", () => {
    const tree = parse("select 5");
    expect(tree).to.deep.equal([
      new AST.SelectStatement({
        arguments: [new AST.Number(5)],
      }),
    ]);
  });

  it("should parse a multiple number selection", () => {
    const tree = parse("select 5, 6");
    expect(tree).to.deep.equal([
      new AST.SelectStatement({
        arguments: [new AST.Number(5), new AST.Number(6)],
      }),
    ]);
  });

  it("should parse a selection of identifiers", () => {
    const tree = parse("select a, b");
    expect(tree).to.deep.equal([
      new AST.SelectStatement({
        arguments: [new AST.Identifier("a"), new AST.Identifier("b")],
      }),
    ]);
  });

  it("should parse a selection of identifiers and numbers", () => {
    const tree = parse("select a, 5");
    expect(tree).to.deep.equal([
      new AST.SelectStatement({
        arguments: [new AST.Identifier("a"), new AST.Number(5)],
      }),
    ]);
  });

  it("should parse the from of a selection", () => {
    const tree = parse("select a from t");
    expect(tree).to.deep.equal([
      new AST.SelectStatement({
        arguments: [new AST.Identifier("a")],
        from: new AST.Identifier("t"),
      }),
    ]);
  });

  it("should parse aliases", () => {
    const tree = parse("select a as b");
    expect(tree).to.deep.equal([
      new AST.SelectStatement({
        arguments: [
          new AST.Alias(new AST.Identifier("a"), new AST.Identifier("b")),
        ],
      }),
    ]);
  });

  it("should parse aliases as from targets", () => {
    const tree = parse("select a from t as u");
    expect(tree).to.deep.equal([
      new AST.SelectStatement({
        arguments: [new AST.Identifier("a")],
        from: new AST.Alias(new AST.Identifier("t"), new AST.Identifier("u")),
      }),
    ]);
  });

  it("should not allow a number as a from target", () => {
    const fn = () => parse("select 1 from 2");
    expect(fn).to.throw("Unexpected token: { kind: NUMBER, value: 2 }");
  });

  it("should parse a where with a number", () => {
    const tree = parse("select a from b where 1");
    expect(tree).to.deep.equal([
      new AST.SelectStatement({
        arguments: [new AST.Identifier("a")],
        from: new AST.Identifier("b"),
        where: new AST.Number(1),
      }),
    ]);
  });

  it("should parse a where with an identifier", () => {
    const tree = parse("select a from b where c");
    expect(tree).to.deep.equal([
      new AST.SelectStatement({
        arguments: [new AST.Identifier("a")],
        from: new AST.Identifier("b"),
        where: new AST.Identifier("c"),
      }),
    ]);
  });
});