add test for single body

src/main.zig

@@ -351,7 +351,7 @@ test "multipart" {
         "Hello!\n";
 
     const PART2_REAL_BODY =
-        "{\"status\": \"OK\"}\n";
+        "{\"status\": \"OK\"}";
 
     const body =
         "--1234\r\n" ++
@@ -407,3 +407,42 @@ test "multipart" {
         try multipart.next(&hzzp_buffer, std.testing.allocator),
     );
 }
+
+test "multipart single file" {
+    const PART1_REAL_BODY =
+        "Hello!";
+
+    const body =
+        "--1234\r\n" ++
+        "Content-Type: text/plain\r\n" ++
+        "Content-Disposition: form-data; name=file1; filename=ab.txt\r\n" ++
+        "\r\n" ++
+        PART1_REAL_BODY ++
+        "--1234--\r\n";
+
+    var buf: [512]u8 = undefined;
+    var multipart = try Multipart.init(
+        body,
+        "multipart/form-data; boundary=1234",
+        &buf,
+    );
+
+    var hzzp_buffer: [1024]u8 = undefined;
+    var part1 = (try multipart.next(&hzzp_buffer, std.testing.allocator)).?;
+    defer part1.deinit();
+
+    std.debug.warn(
+        "\npart={}\n",
+        .{part1},
+    );
+
+    std.testing.expectEqualSlices(u8, "text/plain", part1.content_type);
+    std.testing.expectEqualSlices(u8, "file1", part1.disposition.name);
+    std.testing.expectEqualSlices(u8, "ab.txt", part1.disposition.filename);
+    std.testing.expectEqualSlices(u8, PART1_REAL_BODY, part1.body);
+
+    std.testing.expectEqual(
+        @as(?Part, null),
+        try multipart.next(&hzzp_buffer, std.testing.allocator),
+    );
+}