jtr/DevDisciples.Json.Parser.Tests/JsonParserTests.cs

namespace DevDisciples.Json.Parser.Tests;

public class JsonParserTests
{
    [SetUp]
    public void Setup()
    {
    }

    [Test]
    public void Can_parse_null()
    {
        const string source = "null";
        var node = JsonParser.Parse(nameof(Can_parse_null), source);
        Assert.That(node is JsonNull);
    }

    [Test]
    public void Can_parse_booleans()
    {
        const string trueSource = "true";
        const string falseSource = "false";
        var trueNode = JsonParser.Parse(nameof(Can_parse_booleans), trueSource);
        var falseNode = JsonParser.Parse(nameof(Can_parse_booleans), falseSource);

        Assert.Multiple(() =>
        {
            Assert.That(trueNode is JsonBool { Value: true });
            Assert.That(falseNode is JsonBool { Value: false });
        });
    }

    [Test]
    public void Can_parse_an_integer()
    {
        const string source = "1";
        var node = JsonParser.Parse(nameof(Can_parse_an_integer), source);
        Assert.That(node is JsonNumber { Value: 1 });
    }

    [Test]
    public void Can_lex_a_decimal()
    {
        const string source = "1.0";
        var node = JsonParser.Parse(nameof(Can_lex_a_decimal), source);
        Assert.That(node is JsonNumber { Value: 1.0 });
    }

    [Test]
    public void Can_parse_a_string()
    {
        const string source = "\"Hello world!\"";
        var tokens = JsonParser.Parse(nameof(Can_parse_a_string), source);
        Assert.That(tokens is JsonString { Value: "Hello world!" });
    }

    [Test]
    public void Can_parse_an_empty_array()
    {
        const string source = "[]";
        var tokens = JsonParser.Parse(nameof(Can_parse_an_empty_array), source);
        Assert.That(tokens is JsonArray);
    }

    [Test]
    public void Can_parse_a_single_item_array()
    {
        const string source = "[1]";
        var tokens = JsonParser.Parse(nameof(Can_parse_a_single_item_array), source);

        Assert.That(tokens is JsonArray
        {
            Elements: [JsonNumber { Value: 1 }]
        });
    }

    [Test]
    public void Can_parse_an_array_with_multiple_items()
    {
        const string source = "[1,true,{},[],null]";
        var node = JsonParser.Parse(nameof(Can_parse_an_array_with_multiple_items), source);

        Assert.That(node is JsonArray
        {
            Elements:
            [
                JsonNumber { Value: 1 },
                JsonBool { Value: true },
                JsonObject { Properties.Length: 0 },
                JsonArray { Elements.Length: 0 },
                JsonNull
            ]
        });
    }

    [Test]
    public void Can_parse_an_empty_object()
    {
        const string source = "{}";
        var tokens = JsonParser.Parse(nameof(Can_parse_an_empty_object), source);
        Assert.That(tokens is JsonObject { Properties.Length: 0 });
    }

    [Test]
    public void Can_parse_an_object_with_one_entry()
    {
        const string source = "{\"first_name\":\"John\"}";
        var node = JsonParser.Parse(nameof(Can_parse_an_object_with_one_entry), source);

        Assert.That(node is JsonObject { Properties.Length: 1 });
        var @object = (JsonObject)node;
        Assert.That(@object.Properties.Any(property => property.Key == "first_name"));
        Assert.That(@object.Properties.First(property => property.Key == "first_name").Value is JsonString { Value: "John" });
    }

    [Test]
    public void Can_parse_an_object_with_multiple_entries()
    {
        const string source = "{\"first_name\":\"John\", \"last_name\": \"Doe\"}";
        var node = JsonParser.Parse(nameof(Can_parse_an_object_with_one_entry), source);

        Assert.Multiple(() =>
        {
            Assert.That(node is JsonObject { Properties.Length: 2 });
            var @object = (JsonObject)node;
            Assert.That(@object.Properties.Any(property => property.Key == "first_name"));
            Assert.That(@object.Properties.First(property => property.Key == "first_name").Value is JsonString { Value: "John" });
            Assert.That(@object.Properties.Any(property => property.Key == "last_name"));
            Assert.That(@object.Properties.First(property => property.Key == "last_name").Value is JsonString { Value: "Doe" });
        });
    }
}