sql/test/lexer.test.ts

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

import Error, { isError } from "../src/error";
import Lexer from "../src/lexer";
import Token, { TokenKind } from "../src/token";

const scan = (source: string): Token[] | Error => {
  return new Lexer(source).scan();
};

describe("Lexer", () => {
  it("scans uppercase keywords", () => {
    const tokens = scan("SELECT FROM WHERE AS AND OR");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.SELECT, null, 1),
      new Token(TokenKind.FROM, null, 1),
      new Token(TokenKind.WHERE, null, 1),
      new Token(TokenKind.AS, null, 1),
      new Token(TokenKind.AND, null, 1),
      new Token(TokenKind.OR, null, 1),
      new Token(TokenKind.EOF, null, 1),
    ]);
  });

  it("scans lowercase keywords", () => {
    const tokens = scan("select from where as and or");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.SELECT, null, 1),
      new Token(TokenKind.FROM, null, 1),
      new Token(TokenKind.WHERE, null, 1),
      new Token(TokenKind.AS, null, 1),
      new Token(TokenKind.AND, null, 1),
      new Token(TokenKind.OR, null, 1),
      new Token(TokenKind.EOF, null, 1),
    ]);
  });

  it("scans symbols", () => {
    const tokens = scan("=,`;.+-*/()");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.EQUALS, null, 1),
      new Token(TokenKind.COMMA, null, 1),
      new Token(TokenKind.BACKTICK, null, 1),
      new Token(TokenKind.SEMICOLON, null, 1),
      new Token(TokenKind.DOT, null, 1),
      new Token(TokenKind.PLUS, null, 1),
      new Token(TokenKind.MINUS, null, 1),
      new Token(TokenKind.STAR, null, 1),
      new Token(TokenKind.SLASH, null, 1),
      new Token(TokenKind.LPAREN, null, 1),
      new Token(TokenKind.RPAREN, null, 1),
      new Token(TokenKind.EOF, null, 1),
    ]);
  });

  it("scans identifiers", () => {
    const tokens = scan("ident ident_ifier Ident");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.IDENTIFIER, "ident", 1),
      new Token(TokenKind.IDENTIFIER, "ident_ifier", 1),
      new Token(TokenKind.IDENTIFIER, "Ident", 1),
      new Token(TokenKind.EOF, null, 1),
    ]);
  });

  it("scans numbers", () => {
    const tokens = scan("1 123.45 .123");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.NUMBER, "1", 1),
      new Token(TokenKind.NUMBER, "123.45", 1),
      new Token(TokenKind.NUMBER, ".123", 1),
      new Token(TokenKind.EOF, null, 1),
    ]);
  });

  it("keeps track of line numbers", () => {
    const tokens = scan("foo\nbar");
    expect(tokens).to.deep.equal([
      new Token(TokenKind.IDENTIFIER, "foo", 1),
      new Token(TokenKind.IDENTIFIER, "bar", 2),
      new Token(TokenKind.EOF, null, 2),
    ]);
  });

  it("returns an error for an unrecognized character", () => {
    const error = scan("~");
    expect(isError(error)).to.be.ok;
    if (isError(error)) {
      expect(error.message).to.equal("Unrecognized character ~");
    }
  });
});