Generate templates

bin/add-practice-exercise.ps1

@@ -46,23 +46,9 @@ $project = "${exerciseDir}/${ExerciseName}.csproj"
 Remove-Item -Path "${exerciseDir}/UnitTest1.cs"
 (Get-Content -Path ".editorconfig") -Replace "\[\*\.cs\]", "[${exerciseName}.cs]" | Set-Content -Path "${exerciseDir}/.editorconfig"
 
-# Add and run generator (this will update the tests file)
-$generator = "${exerciseDir}/.meta/Generator.tpl"
-Add-Content -Path $generator -Value @"
-using Xunit;
-
-public class {{testClass}}
-{
-    {{for test in tests}}
-    [Fact{{if !for.first}}(Skip = "Remove this Skip property to run this test"){{end}}]
-    public void {{test.testMethod}}()
-    {
-        // TODO: implement the test
-    }
-    {{end}}
-}
-"@
-& dotnet run --project generators --exercise $Exercise
+# Create new generator template and run generator (this will update the tests file)
+& dotnet run --project generators new --exercise $Exercise
+& dotnet run --project generators generate --exercise $Exercise
 
 # Output the next steps
 $files = Get-Content "exercises/practice/${Exercise}/.meta/config.json" | ConvertFrom-Json | Select-Object -ExpandProperty files

generators/Exercises.cs

@@ -1,3 +1,5 @@
+using System.Text.Json;
+
 using Humanizer;
 
 namespace Generators;
@@ -6,25 +8,28 @@ internal record Exercise(string Slug, string Name);
 
 internal static class Exercises
 {
-    internal static Exercise[] TemplatedExercises() =>
-        Directory.EnumerateFiles(Paths.PracticeExercisesDir, "Generator.tpl", SearchOption.AllDirectories)
-            .Select(templateFile => Directory.GetParent(templateFile)!.Parent!.Name)
-            .Select(ToExercise)
-            .OrderBy(exercise => exercise.Slug)
-            .ToArray();
-
-    internal static Exercise TemplatedExercise(string slug)
-    {
-        var exercise = ToExercise(slug);
-
-        if (!Directory.Exists(Paths.ExerciseDir(exercise)))
-            throw new ArgumentException($"Could not find exercise '{slug}'.");
-
-        if (!File.Exists(Paths.TemplateFile(exercise)))
-            throw new ArgumentException($"Could not find template file for exercise '{slug}'.");
-
-        return exercise;
-    }
+    internal static List<Exercise> Templated(string? slug = null) => Find(slug, hasTemplate: true);
+
+    internal static List<Exercise> Untemplated(string? slug = null) => Find(slug, hasTemplate: false);
+
+    private static List<Exercise> Find(string? slug, bool hasTemplate) =>
+        Parse()
+            .Where(exercise => slug is null || exercise.Slug == slug)
+            .Where(HasCanonicalData)
+            .Where(exercise => hasTemplate == HasTemplate(exercise))
+            .ToList();
+
+    private static IEnumerable<Exercise> Parse() =>
+        JsonSerializer.Deserialize<JsonElement>(File.ReadAllText(Paths.TrackConfigFile))
+            .GetProperty("exercises")
+            .GetProperty("practice")
+            .EnumerateArray()
+            .Select(exercise => exercise.GetProperty("slug").ToString())
+            .Order()
+            .Select(ToExercise);
 
     private static Exercise ToExercise(string slug) => new(slug, slug.Dehumanize());
+
+    private static bool HasCanonicalData(Exercise exercise) => File.Exists(Paths.CanonicalDataFile(exercise));
+    private static bool HasTemplate(Exercise exercise) => File.Exists(Paths.TemplateFile(exercise));
 }

generators/Paths.cs

@@ -6,7 +6,8 @@ internal static class Paths
     internal static readonly string ProbSpecsDir = Path.Join(RootDir, ".problem-specifications");
     private static readonly string ProbSpecsExercisesDir = Path.Join(ProbSpecsDir, "exercises");
     internal static readonly string PracticeExercisesDir = Path.Join(RootDir, "exercises", "practice");
-
+    internal static readonly string TrackConfigFile = Path.Join(RootDir, "config.json");
+
     internal static string ExerciseDir(Exercise exercise) => Path.Join(PracticeExercisesDir, exercise.Slug);
     internal static string TestsFile(Exercise exercise) => Path.Join(ExerciseDir(exercise), $"{exercise.Name}Tests.cs");
     internal static string TestsTomlFile(Exercise exercise) => Path.Join(ExerciseDir(exercise), ".meta", "tests.toml");

generators/Program.cs

@@ -2,24 +2,34 @@
 
 namespace Generators;
 
-public static class Program 
+public static class Program
 {
-    private class Options
+    static void Main(string[] args) =>
+        Parser.Default.ParseArguments<NewOptions, GenerateOptions>(args)
+            .WithParsed<GenerateOptions>(HandleGenerateCommand)
+            .WithParsed<NewOptions>(HandleNewCommand)
+            .WithNotParsed(HandleErrors);
+
+    private static void HandleGenerateCommand(GenerateOptions options) =>
+        Exercises.Templated(options.Exercise).ForEach(TestsGenerator.Generate);
+
+    private static void HandleNewCommand(NewOptions options) =>
+        Exercises.Untemplated(options.Exercise).ForEach(TemplateGenerator.Generate);
+
+    private static void HandleErrors(IEnumerable<Error> errors) =>
+        errors.ToList().ForEach(Console.Error.WriteLine);
+
+    [Verb("generate", isDefault: true, HelpText = "Generate the test file's contents using the exercise's generator template file.")]
+    private class GenerateOptions
     {
-        [Option('e', "exercise", Required = false, HelpText = "The exercise (slug) to generate the tests file for.")]
+        [Option('e', "exercise", Required = false, HelpText = "The exercise (slug) which tests file to generate.")]
         public string? Exercise { get; set; }
     }
-
-    static void Main(string[] args) =>
-        Parser.Default.ParseArguments<Options>(args)
-            .WithParsed(options =>
-            {
-                foreach (var exercise in Exercises(options))
-                    TestsGenerator.Generate(exercise);
-            });
 
-    private static Exercise[] Exercises(Options options) =>
-        options.Exercise is null
-            ? Generators.Exercises.TemplatedExercises()
-            : [Generators.Exercises.TemplatedExercise(options.Exercise)];
+    [Verb("new", HelpText = "Create a new exercise generator template file.")]
+    private class NewOptions
+    {
+        [Option('e', "exercise", Required = false, HelpText = "The exercise (slug) for which to generate a generator file.")]
+        public string? Exercise { get; set; }
+    }
 }

generators/TemplateGenerator.cs

@@ -0,0 +1,85 @@
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+using Scriban;
+
+namespace Generators;
+
+internal static class TemplateGenerator
+{
+    internal static void Generate(Exercise exercise)
+    {
+        Console.WriteLine($"{exercise.Slug}: generating template...");
+
+        var canonicalData = CanonicalDataParser.Parse(exercise);
+        var filteredCanonicalData = TestCasesConfiguration.RemoveExcludedTestCases(canonicalData);
+
+        var template = RenderTemplate(filteredCanonicalData);
+        File.WriteAllText(Paths.TemplateFile(exercise), template);
+    }
+
+    private static string RenderTemplate(CanonicalData canonicalData)
+    {
+        var error = canonicalData.TestCases.Where(ExpectsError).Any();
+        var testCase = canonicalData.TestCases.First(testCase => !ExpectsError(testCase));
+        var model = new { error, assert = Assertion(testCase), throws = AssertThrows(testCase) };
+
+        var template = Template.Parse(GeneratorTemplate);
+        return template.Render(model).Trim() + Environment.NewLine;
+    }
+
+    private static string Value(string field, JsonNode? testCase) =>
+        testCase is not null && testCase.GetValueKind() == JsonValueKind.String
+            ? $"{{{{{field} | string.literal}}}}"
+            : $"{{{{{field}}}}}";
+
+    private static string Expected(JsonNode testCase) => Value("test.expected", testCase["expected"]);
+
+    private static string Assertion(JsonNode testCase) =>
+        testCase["expected"]!.GetValueKind() switch
+        {
+            JsonValueKind.False or JsonValueKind.True => AssertBool(testCase),
+            _ => AssertEqual(testCase)
+        };
+
+    private static string TestedMethodArguments(JsonNode testCase) =>
+        string.Join(", ", testCase["input"]!.AsObject().Select(kv => Value($"test.input.{kv.Key}", kv.Value!)));
+
+    private static string TestedMethodCall(JsonNode testCase) =>
+        $"{{{{testedClass}}}}.{{{{test.testedMethod}}}}({TestedMethodArguments(testCase)})";
+
+    private static string AssertBool(JsonNode testCase) =>
+        $"Assert.{{{{test.expected ? \"True\" : \"False\"}}}}({TestedMethodCall(testCase)});";
+
+    private static string AssertEqual(JsonNode testCase) =>
+        $"Assert.Equal({Expected(testCase)}, {TestedMethodCall(testCase)});";
+
+    private static string AssertThrows(JsonNode testCase) =>
+        $"Assert.Throws<ArgumentException>(() => {TestedMethodCall(testCase)});";
+
+    private static bool ExpectsError(this JsonNode testCase) =>
+        testCase["expected"] is JsonObject jsonObject && jsonObject.ContainsKey("error");
+
+    private const string GeneratorTemplate = @"
+{{if error}}using System;{{end}}
+using Xunit;
+
+public class {%{{{testClass}}}%}
+{
+    {%{{{for test in tests}}}%}
+    [Fact{%{{{if !for.first}}}%}(Skip = ""Remove this Skip property to run this test""){%{{{end}}}%}]
+    public void {%{{{test.testMethod}}}%}()
+    {
+        {{-if error}}
+        {%{{{if test.expected.error}}}%}
+            {{throws}}
+        {%{{{else}}}%}
+            {{assert}}
+        {%{{{end}}}%}
+        {{-else}}
+        {{assert}}
+        {{-end}}
+    }
+    {%{{{end}}}%}
+}";
+}