Fix corner cases in developer categories

- If there is only one developer, it is classified as 'core'.
- If there is a list of people with the exact same number of
  contributions and not all of them can enter the 'core' group,
  the first one is selected and the next ones are assigned to 'regular'.

Signed-off-by: Eva Millán <[email protected]>

Author: evamillan

tests/unit/test_metrics.py

@@ -168,6 +168,70 @@ def test_get_developer_categories(self):
         categories = self.analyzer.get_developer_categories()
         self.assertDictEqual(categories, {"core": 2, "regular": 1, "casual": 1})
 
+    def test_get_categories_one_developer(self):
+        """Test if the categories are calculated correctly when there is only one developer"""
+
+        categories = self.analyzer.get_developer_categories()
+        self.assertDictEqual(categories, {"core": 0, "regular": 0, "casual": 0})
+
+        # Add a core developer with 100% of the contributions
+        extra_events = [
+            {
+                "type": "org.grimoirelab.events.git.commit",
+                "data": {"Author": "Author 1 <author1@example_new.com>", "message": "Another commit"},
+            },
+            {
+                "type": "org.grimoirelab.events.git.commit",
+                "data": {"Author": "Author 1 <author1@example_new.com>", "message": "Another commit"},
+            },
+            {
+                "type": "org.grimoirelab.events.git.commit",
+                "data": {"Author": "Author 1 <author1@example_new.com>", "message": "Another commit"},
+            },
+            {
+                "type": "org.grimoirelab.events.git.commit",
+                "data": {"Author": "Author 1 <author1@example_new.com>", "message": "Another commit"},
+            },
+        ]
+
+        self.analyzer.process_events(extra_events)
+        categories = self.analyzer.get_developer_categories()
+        self.assertDictEqual(categories, {"core": 1, "regular": 0, "casual": 0})
+
+    def test_get_developer_categories_tied(self):
+        """Test if the categories are calculated correctly when the core developers have the same contributions"""
+
+        categories = self.analyzer.get_developer_categories()
+        self.assertDictEqual(categories, {"core": 0, "regular": 0, "casual": 0})
+
+        # Add core developers with the same number of contributions
+        extra_events = [
+            {
+                "type": "org.grimoirelab.events.git.commit",
+                "data": {"Author": "Author 1 <author1@example_new.com>", "message": "Another commit"},
+            },
+            {
+                "type": "org.grimoirelab.events.git.commit",
+                "data": {"Author": "Author 2 <author2@example_new.com>", "message": "Another commit"},
+            },
+            {
+                "type": "org.grimoirelab.events.git.commit",
+                "data": {"Author": "Author 3 <author3@example_new.com>", "message": "Another commit"},
+            },
+            {
+                "type": "org.grimoirelab.events.git.commit",
+                "data": {"Author": "Author 4 <author4@example_new.com>", "message": "Another commit"},
+            },
+            {
+                "type": "org.grimoirelab.events.git.commit",
+                "data": {"Author": "Author 5 <author5@example_new.com>", "message": "Another commit"},
+            },
+        ]
+
+        self.analyzer.process_events(extra_events)
+        categories = self.analyzer.get_developer_categories()
+        self.assertDictEqual(categories, {"core": 4, "regular": 1, "casual": 0})
+
 
 if __name__ == "__main__":
     unittest.main()

trustable_cli/metrics.py

@@ -158,13 +158,15 @@ def get_developer_categories(self):
         regular_threshold = int(0.8 * self.total_commits)
         casual_threshold = int(0.95 * self.total_commits)
         acc_commits = 0
+        last_core_contribution = 0
 
         for _, contributions in self.contributors.most_common():
             acc_commits += contributions
 
-            if acc_commits <= regular_threshold:
+            if acc_commits <= regular_threshold or contributions > last_core_contribution:
+                last_core_contribution = contributions
                 core += 1
-            elif acc_commits <= casual_threshold:
+            elif acc_commits <= casual_threshold or contributions == last_core_contribution:
                 regular += 1
             else:
                 casual += 1