pyscript/pyscriptjs/tests/unit/stdio.test.ts

import { expect } from '@jest/globals';
import { type Stdio, CaptureStdio, StdioMultiplexer, TargetedStdio } from '../../src/stdio';

describe('CaptureStdio', () => {
    it('captured streams are initialized to empty string', () => {
        let stdio = new CaptureStdio();
        expect(stdio.captured_stdout).toBe("");
        expect(stdio.captured_stderr).toBe("");
    });

    it('stdout() and stderr() captures', () => {
        let stdio = new CaptureStdio();
        stdio.stdout_writeline("hello");
        stdio.stdout_writeline("world");
        stdio.stderr_writeline("this is an error");
        expect(stdio.captured_stdout).toBe("hello\nworld\n");
        expect(stdio.captured_stderr).toBe("this is an error\n");
    });

    it('reset() works', () => {
        let stdio = new CaptureStdio();
        stdio.stdout_writeline("aaa");
        stdio.stderr_writeline("bbb");
        stdio.reset();
        expect(stdio.captured_stdout).toBe("");
        expect(stdio.captured_stderr).toBe("");
    });

});


describe('StdioMultiplexer', () => {
    let a: CaptureStdio;
    let b: CaptureStdio;
    let multi: StdioMultiplexer;

    beforeEach(() => {
        a = new CaptureStdio();
        b = new CaptureStdio();
        multi = new StdioMultiplexer();
    });

    it('works without listeners', () => {
        // no listeners, messages are ignored
        multi.stdout_writeline('out 1');
        multi.stderr_writeline('err 1');
        expect(a.captured_stdout).toBe("");
        expect(a.captured_stderr).toBe("");
        expect(b.captured_stdout).toBe("");
        expect(b.captured_stderr).toBe("");
    });

    it('redirects to multiple listeners', () => {
        multi.addListener(a);
        multi.stdout_writeline('out 1');
        multi.stderr_writeline('err 1');

        multi.addListener(b);
        multi.stdout_writeline('out 2');
        multi.stderr_writeline('err 2');

        expect(a.captured_stdout).toBe("out 1\nout 2\n");
        expect(a.captured_stderr).toBe("err 1\nerr 2\n");

        expect(b.captured_stdout).toBe("out 2\n");
        expect(b.captured_stderr).toBe("err 2\n");
    });
});

describe('TargetedStdio', () => {
    let capture: CaptureStdio;
    let targeted: TargetedStdio;
    let error_targeted: TargetedStdio;
    let multi: StdioMultiplexer;

    beforeEach(() => {
        //DOM element to capture stdout and stderr
        let target_div = document.getElementById("output-id");

        if (target_div=== null){
            target_div = document.createElement('div');
            target_div.id = "output-id";
            document.body.appendChild(target_div);
        }
        else {
            target_div.innerHTML = "";
        }

        //DOM element to capture stderr
        let error_div = document.getElementById("error-id");

        if (error_div=== null){
            error_div = document.createElement('div');
            error_div.id = "error-id";
            document.body.appendChild(error_div);
        }
        else {
            error_div.innerHTML = "";
        }

        const tag = document.createElement('div');
        tag.setAttribute("output", "output-id");
        tag.setAttribute("stderr", "error-id");

        capture = new CaptureStdio();
        targeted = new TargetedStdio(tag, 'output', true, true);
        error_targeted = new TargetedStdio(tag, 'stderr', false, true);

        multi = new StdioMultiplexer();
        multi.addListener(capture);
        multi.addListener(targeted);
        multi.addListener(error_targeted);
    });

    it('targeted id is set by constructor', () =>{
        expect(targeted.source_attribute).toBe("output");
    });

    it('targeted stdio/stderr also goes to multiplexer', () =>{
        multi.stdout_writeline("out 1");
        multi.stderr_writeline("out 2");
        expect(capture.captured_stdout).toBe("out 1\n");
        expect(capture.captured_stderr).toBe("out 2\n");
        expect(document.getElementById("output-id")?.innerHTML).toBe("out 1<br>out 2<br>");
        expect(document.getElementById("error-id")?.innerHTML).toBe("out 2<br>");
    });

    it('Add and remove targeted listener', () => {
        multi.stdout_writeline("out 1");
        multi.removeListener(targeted);
        multi.stdout_writeline("out 2");
        multi.addListener(targeted);
        multi.stdout_writeline("out 3");

        //all three should be captured by multiplexer
        expect(capture.captured_stdout).toBe("out 1\nout 2\nout 3\n");
        //out 2 should not be present in the DOM element
        expect(document.getElementById("output-id")?.innerHTML).toBe("out 1<br>out 3<br>");
    });
});