fix(#352): fix content-length in Range requests (#353)

Author: aperiosio

send.ts

@@ -127,7 +127,7 @@ async function sendRange(
     const [byteRange] = ranges;
     response.headers.set(
       "Content-Length",
-      String(byteRange.end - byteRange.start),
+      String(byteRange.end - byteRange.start + 1),
     );
     response.headers.set(
       "Content-Range",

send_test.ts

@@ -482,11 +482,26 @@ test({
     const response = await context.response.toDomResponse();
     assertEquals(response.status, 206);
     assertEquals(context.response.type, ".json");
-    assertEquals(context.response.headers.get("content-length"), "5");
+    assertEquals(context.response.headers.get("content-length"), "6");
     assertEquals(await response.text(), `{\n  "h`);
   },
 });
 
+test({
+  name: "range header from 0-",
+  ignore: Deno.build.os === "windows",
+  async fn() {
+    const { context } = setup("/test.json");
+    context.request.headers.set("Range", "bytes=0-");
+    await send(context, context.request.url.pathname, { root: "./fixtures" });
+    const response = await context.response.toDomResponse();
+    assertEquals(response.status, 206);
+    assertEquals(context.response.type, ".json");
+    assertEquals(context.response.headers.get("content-length"), "23");
+    assertEquals(await response.text(), `{\n  "hello": "world"\n}\n`);
+  },
+});
+
 test({
   name: "range header - multiple ranges",
   ignore: Deno.build.os === "windows",