1 files changed, 61 insertions, 0 deletions
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java
new file mode 100644
index 0000000..0a614f4
--- /dev/null
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java
@@ -0,0 +1,61 @@
+package org.zwobble.hobgoblin.compiler.output.lang.java;
+
+import org.junit.jupiter.api.Test;
+import org.zwobble.hobgoblin.compiler.output.CodeWriter;
+import org.zwobble.hobgoblin.compiler.output.lang.java.ast.JavaInterfaceDeclaration;
+import org.zwobble.hobgoblin.compiler.output.lang.java.ast.JavaTypeRef;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.util.List;
+
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.equalTo;
+
+public class JavaWriterTests {
+    @Test
+    public void emptyInterfaceDeclaration() throws IOException {
+        var java = new JavaInterfaceDeclaration(
+            "Shape",
+            List.of()
+        );
+
+        var string = write(writer -> writer.writeTypeDeclaration(java));
+
+        assertThat(string, equalTo("""
+            public sealed interface Shape {
+            }
+            """
+        ));
+    }
+
+    @Test
+    public void sealedInterfaceDeclarationWithPermitsTypes() throws IOException {
+        var java = new JavaInterfaceDeclaration(
+            "Shape",
+            List.of(
+                new JavaTypeRef(List.of("abc", "def"), "One"),
+                new JavaTypeRef(List.of("abc", "def"), "Two")
+            )
+        );
+
+        var string = write(writer -> writer.writeTypeDeclaration(java));
+
+        assertThat(string, equalTo("""
+            public sealed interface Shape permits abc.def.One, abc.def.Two {
+            }
+            """
+        ));
+    }
+
+    private String write(Write write) throws IOException {
+        var stringWriter = new StringWriter();
+        var javaWriter = new JavaWriter(new CodeWriter(stringWriter));
+        write.write(javaWriter);
+        return stringWriter.toString();
+    }
+
+    private interface Write {
+        void write(JavaWriter writer) throws IOException;
+    }
+}