fix: empty lineages can be uncompressed

src/pango_aliasor/README.md

@@ -0,0 +1,13 @@
+## Testing
+
+Run `pytest` from the project root to run all tests.
+
+## Release
+
+```bash
+pip install build
+python -m build --sdist --outdir dist .
+pip install twine
+rm -rf dist
+twine upload dist/*
+```

src/pango_aliasor/aliasor.py

@@ -29,7 +29,7 @@ def compress(self,name):
         name_split = name.split('.')
         levels = len(name_split) - 1
         num_indirections = (levels -1) // 3
-        if num_indirections == 0:
+        if num_indirections <= 0:
             return name
         alias = ".".join(name_split[0:(3*num_indirections + 1)])
         ending = ".".join(name_split[(3*num_indirections + 1):])
@@ -38,7 +38,10 @@ def compress(self,name):
     def uncompress(self,name):
         name_split = name.split('.')
         letter = name_split[0]
-        unaliased = self.alias_dict[letter]
+        try:
+            unaliased = self.alias_dict[letter]
+        except KeyError:
+            return name
         if len(name_split) == 1:
             return name
         if len(name_split) == 2:

tests/test_aliasor.py

@@ -9,6 +9,8 @@ def test_uncompression():
     assert aliasor.uncompress('AY.4') == 'B.1.617.2.4'
     assert aliasor.uncompress('AY.4.3.2') == 'B.1.617.2.4.3.2'
     assert aliasor.uncompress('B.1') == 'B.1'
+    assert aliasor.uncompress('B') == 'B'
+    assert aliasor.uncompress('') == ''
 
 def test_compression():
     aliasor = Aliasor()
@@ -17,6 +19,8 @@ def test_compression():
     assert aliasor.compress('B.1.617.2.4.3.1') == 'AY.4.3.1'
     assert aliasor.compress('B.1.617.2') == 'B.1.617.2'
     assert aliasor.compress('B.1') == 'B.1'
+    assert aliasor.compress('B') == 'B'
+    assert aliasor.compress('') == ''
 
 def test_except_recombinants():
     aliasor = Aliasor()