From e3fe04bb3bff91f46857b2fee4d698875ef18d22 Mon Sep 17 00:00:00 2001
From: vitous <vitous@isibrno.cz>
Date: Thu, 30 Jul 2026 15:23:23 +0200
Subject: [PATCH] =?UTF-8?q?`JCAMPDX`=20has=20`keys()`=20and=20`=5F=5Fgetit?=
 =?UTF-8?q?em=5F=5F`=20but=20no=20`=5F=5Fiter=5F=5F`=20=E2=80=94=20`for=20?=
 =?UTF-8?q?key=20in=20jcampdx`=20raises=20`KeyError:=200`=20Fixes=20#184?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 brukerapi/jcampdx.py |  6 ++++++
 test/test_jcampdx.py | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/brukerapi/jcampdx.py b/brukerapi/jcampdx.py
index 1fc89e8..8b41a81 100644
--- a/brukerapi/jcampdx.py
+++ b/brukerapi/jcampdx.py
@@ -704,6 +704,12 @@ def __add__(self, other):
     def __getitem__(self, key):
         return self.params[key]
 
+    def __iter__(self):
+        return iter(self.params)
+
+    def __len__(self):
+        return len(self.params)
+
     def __contains__(self, item):
         return item in self.params
 
diff --git a/test/test_jcampdx.py b/test/test_jcampdx.py
index 8a0e0b0..3717fca 100644
--- a/test/test_jcampdx.py
+++ b/test/test_jcampdx.py
@@ -48,6 +48,26 @@ def test_jcampdx(test_jcampdx_data):
             assert value_ref == value_test
 
 
+def test_jcampdx_iteration_and_length_follow_its_mapping_interface(tmp_path):
+    path = tmp_path / "visu_pars"
+    path.write_text(
+        "##TITLE=Parameter List\n"
+        "##JCAMPDX=4.24\n"
+        "##DATATYPE=Parameter Values\n"
+        "##$VisuCoreDim=2\n"
+        "##END=\n"
+    )
+    jcamp = JCAMPDX(path)
+
+    assert list(jcamp) == list(jcamp.keys())
+    assert len(jcamp) == len(jcamp.keys())
+    assert dict(jcamp) == {key: jcamp[key] for key in jcamp}
+
+    jcamp.unload()
+    assert list(jcamp) == []
+    assert len(jcamp) == 0
+
+
 def test_a_string_is_read_without_its_delimiters():
     """Spec 2.2: `<...>` delimits a string, so the brackets are not its value.