LspTest.java

package org.javacs.lsp;

import static org.hamcrest.Matchers.*;
import static org.hamcrest.MatcherAssert.assertThat;

import com.google.gson.Gson;
import com.google.gson.JsonObject;
import java.io.IOException;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.nio.charset.StandardCharsets;
import java.util.Optional;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

public class LspTest {

    private static final Gson gson = new Gson();
    PipedInputStream buffer = new PipedInputStream(10 * 1024 * 1024); // 10 MB buffer
    PipedOutputStream writer = new PipedOutputStream();

    @Before
    public void connectBuffer() throws IOException {
        writer.connect(buffer);
    }

    String bufferToString() {
        try {
            var available = buffer.available();
            var bytes = new byte[available];
            var read = buffer.read(bytes);
            assert read == available;
            return new String(bytes, StandardCharsets.UTF_8);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @After
    public void cleanup() throws IOException {
        buffer.close();
        writer.close();
    }

    @Test
    public void writeResponse() {
        LSP.respond(writer, 1, 2);
        var expected = "Content-Length: 35\r\n\r\n{\"jsonrpc\":\"2.0\",\"id\":1,\"result\":2}";
        assertThat(bufferToString(), equalTo(expected));
    }

    @Test
    public void writeError() {
        LSP.error(writer, 1, new ResponseError(-100, "something went wrong", null));
        var expected =
                "Content-Length: 79\r\n\r\n{\"jsonrpc\":\"2.0\",\"id\":1,\"error\":{\"code\":-100,\"message\":\"something went wrong\"}}";
        assertThat(bufferToString(), equalTo(expected));
    }

    @Test
    public void writeMultibyteCharacters() {
        LSP.respond(writer, 1, "🔥");
        var expected = "Content-Length: 40\r\n\r\n{\"jsonrpc\":\"2.0\",\"id\":1,\"result\":\"🔥\"}";
        assertThat(bufferToString(), equalTo(expected));
    }

    @Test
    public void writeOptional() {
        LSP.respond(writer, 1, Optional.of(1));
        var expected = "Content-Length: 35\r\n\r\n{\"jsonrpc\":\"2.0\",\"id\":1,\"result\":1}";
        assertThat(bufferToString(), equalTo(expected));
    }

    @Test
    public void writeEmpty() {
        LSP.respond(writer, 1, Optional.empty());
        var expected = "Content-Length: 38\r\n\r\n{\"jsonrpc\":\"2.0\",\"id\":1,\"result\":null}";
        assertThat(bufferToString(), equalTo(expected));
    }

    @Test
    public void readMessage() throws IOException {
        var message = "{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"initialize\",\"params\":{}}";
        var header = String.format("Content-Length: %d\r\n\r\n", message.getBytes().length);
        writer.write(header.getBytes());
        writer.write(message.getBytes());

        var token = LSP.nextToken(buffer);
        assertThat(token, equalTo(message));

        var parse = LSP.parseMessage(token);
        assertThat(parse.jsonrpc, equalTo("2.0"));
        assertThat(parse.id, equalTo(1));
        assertThat(parse.method, equalTo("initialize"));
        assertThat(parse.params, equalTo(new JsonObject()));
    }

    @Test
    public void readMessageWithMultiBytesCharacters() throws IOException {
        var params = new ShowMessageParams();
        params.message = "🔥";
        var message =
                String.format(
                        "{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"initialize\",\"params\": %s}", gson.toJson(params));
        var header = String.format("Content-Length: %d\r\n\r\n", message.getBytes().length);
        writer.write(header.getBytes());
        writer.write(message.getBytes());

        var token = LSP.nextToken(buffer);
        assertThat(token, equalTo(message));

        var parse = LSP.parseMessage(token);
        assertThat(parse.jsonrpc, equalTo("2.0"));
        assertThat(parse.id, equalTo(1));
        assertThat(parse.method, equalTo("initialize"));
        assertThat(parse.params, equalTo(gson.toJsonTree(params)));
    }

    @Test
    public void excludeDefaults() {
        var item = new CompletionItem();
        var text = LSP.toJson(item);

        assertThat(text, equalTo("{\"kind\":0}"));
    }
}