Implement comparison operator for StrainCollection class (#111)

* Implement comparison operator for `StrainCollection` class
Fixes #110

* Update src/nplinker/strains.py

Co-authored-by: Cunliang Geng <c.geng@esciencecenter.nl>

---------

Co-authored-by: Cunliang Geng <c.geng@esciencecenter.nl>

src/nplinker/strain_collection.py

@@ -210,3 +210,9 @@ def __str__(self):
 
         return f'StrainCollection(n={len(self)}) [' + ','.join(
             s.id for s in self._strains) + ']'
+
+    def __eq__(self, other):
+        result = self._strains == other._strains
+        result &= self._lookup == other._lookup
+        result &= self._lookup_indices == other._lookup_indices
+        return result

src/nplinker/strains.py

@@ -38,3 +38,10 @@ def __repr__(self) -> str:
 
     def __str__(self) -> str:
         return f'Strain({self.id}) [{len(self.aliases)} aliases]'
+
+    def __eq__(self, other):
+        return (
+            isinstance(other, Strain)
+            and self.id == other.id
+            and self.aliases == other.aliases
+        )

tests/test_strain.py

@@ -19,3 +19,10 @@ def test_has_alias(strain: Strain, alias: str, expected: bool):
 def test_add_alias(strain: Strain):
     strain.add_alias("test")
     assert len(strain.aliases) == 2
+
+
+def test_equal(strain: Strain):
+    other = Strain("peter")
+    other.add_alias("dieter")
+
+    assert strain == other

tests/test_strain_collection.py

@@ -1,6 +1,7 @@
 import pytest
 from nplinker.strain_collection import StrainCollection
 from nplinker.strains import Strain
+from tests import DATA_DIR
 
 
 @pytest.fixture
@@ -68,3 +69,10 @@ def test_remove(collection: StrainCollection, strain: Strain):
 
     # needs fixing, see #90
     assert collection.lookup_index(0) == strain
+
+
+def test_equal(collection_from_file: StrainCollection):
+    other = StrainCollection()
+    other.add_from_file(DATA_DIR / "strain_mappings.csv")
+
+    assert collection_from_file == other