Expand Gotlin language and tooling

internal/lang/json_decode_test.go

@@ -0,0 +1,31 @@
+package lang
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestGenerateGoJSONDecodeReturnsTypedValue(t *testing.T) {
+	prog, err := Parse(`
+package demo
+
+import json encoding.json
+
+fun decode(body: ByteSlice): List<Account> {
+    val accounts = json.decode<List<Account>>(body)
+    return accounts
+}
+`)
+	if err != nil {
+		t.Fatalf("parse failed: %v", err)
+	}
+	out, err := GenerateGo(prog)
+	if err != nil {
+		t.Fatalf("generation failed: %v", err)
+	}
+	for _, want := range []string{"accounts := gotlinAutoThrow(gotlinJSONDecode[[]Account](body))", "json.Unmarshal(body, &value)"} {
+		if !strings.Contains(string(out), want) {
+			t.Fatalf("generated Go missing %q:\n%s", want, out)
+		}
+	}
+}