diff --git a/tests/test_models.py b/tests/test_models.py
new file mode 100644
index 0000000..f0b99a1
--- /dev/null
+++ b/tests/test_models.py
@@ -0,0 +1,205 @@
+"""Tests for data models."""
+
+import pytest
+from datetime import datetime
+
+from repohealth.models.file_stats import FileAnalysis
+from repohealth.models.author import AuthorStats
+from repohealth.models.result import RepositoryResult, RiskLevel
+
+
+class TestFileAnalysis:
+    """Tests for FileAnalysis model."""
+
+    def test_file_analysis_creation(self):
+        """Test creating a FileAnalysis instance."""
+        analysis = FileAnalysis(
+            path="src/main.py",
+            total_commits=10,
+            author_commits={"author1@example.com": 6, "author2@example.com": 4}
+        )
+
+        assert analysis.path == "src/main.py"
+        assert analysis.total_commits == 10
+        assert analysis.num_authors == 2
+        assert analysis.bus_factor == 1.0
+
+    def test_num_authors(self):
+        """Test num_authors property."""
+        analysis = FileAnalysis(
+            path="test.py",
+            total_commits=5,
+            author_commits={"a@x.com": 3, "b@x.com": 2}
+        )
+
+        assert analysis.num_authors == 2
+
+    def test_num_authors_empty(self):
+        """Test num_authors with empty commits."""
+        analysis = FileAnalysis(
+            path="test.py",
+            total_commits=0,
+            author_commits={}
+        )
+
+        assert analysis.num_authors == 0
+
+    def test_top_author(self):
+        """Test top_author property."""
+        analysis = FileAnalysis(
+            path="test.py",
+            total_commits=10,
+            author_commits={"a@x.com": 7, "b@x.com": 3}
+        )
+
+        top_author, count = analysis.top_author
+        assert top_author == "a@x.com"
+        assert count == 7
+
+    def test_top_author_empty(self):
+        """Test top_author with empty commits."""
+        analysis = FileAnalysis(
+            path="test.py",
+            total_commits=0,
+            author_commits={}
+        )
+
+        assert analysis.top_author is None
+
+    def test_top_author_share(self):
+        """Test top_author_share property."""
+        analysis = FileAnalysis(
+            path="test.py",
+            total_commits=10,
+            author_commits={"a@x.com": 8, "b@x.com": 2}
+        )
+
+        assert analysis.top_author_share == 0.8
+
+    def test_top_author_share_empty(self):
+        """Test top_author_share with no commits."""
+        analysis = FileAnalysis(
+            path="test.py",
+            total_commits=0,
+            author_commits={}
+        )
+
+        assert analysis.top_author_share == 0.0
+
+    def test_get_author_share(self):
+        """Test get_author_share method."""
+        analysis = FileAnalysis(
+            path="test.py",
+            total_commits=10,
+            author_commits={"a@x.com": 5, "b@x.com": 5}
+        )
+
+        assert analysis.get_author_share("a@x.com") == 0.5
+        assert analysis.get_author_share("b@x.com") == 0.50
+        assert analysis.get_author_share("c@x.com") == 0.0
+
+    def test_module_and_extension(self):
+        """Test module and extension extraction."""
+        analysis = FileAnalysis(
+            path="src/core/main.py",
+            total_commits=5,
+            author_commits={},
+            module="src/core",
+            extension="py"
+        )
+
+        assert analysis.module == "src/core"
+        assert analysis.extension == "py"
+
+
+class TestAuthorStats:
+    """Tests for AuthorStats model."""
+
+    def test_author_stats_creation(self):
+        """Test creating an AuthorStats instance."""
+        stats = AuthorStats(
+            name="Test Author",
+            email="test@example.com",
+            total_commits=100
+        )
+
+        assert stats.name == "Test Author"
+        assert stats.email == "test@example.com"
+        assert stats.total_commits == 100
+        assert len(stats.files_touched) == 0
+
+    def test_add_file(self):
+        """Test adding a file contribution."""
+        stats = AuthorStats(name="Test", email="test@test.com")
+        stats.add_file("src/main.py", "src")
+
+        assert "src/main.py" in stats.files_touched
+        assert "src" in stats.modules_contributed
+        assert stats.total_contributions == 1
+
+    def test_merge(self):
+        """Test merging two AuthorStats."""
+        stats1 = AuthorStats(name="Test", email="test@test.com")
+        stats1.total_commits = 10
+        stats1.files_touched = {"file1.py"}
+
+        stats2 = AuthorStats(name="Test", email="test@test.com")
+        stats2.total_commits = 5
+        stats2.files_touched = {"file2.py"}
+
+        stats1.merge(stats2)
+
+        assert stats1.total_commits == 15
+        assert "file1.py" in stats1.files_touched
+        assert "file2.py" in stats1.files_touched
+
+
+class TestRepositoryResult:
+    """Tests for RepositoryResult model."""
+
+    def test_repository_result_creation(self):
+        """Test creating a RepositoryResult instance."""
+        result = RepositoryResult(
+            repository_path="/test/repo",
+            files_analyzed=100,
+            total_commits=500,
+            unique_authors=5
+        )
+
+        assert result.repository_path == "/test/repo"
+        assert result.files_analyzed == 100
+        assert result.total_commits == 500
+        assert result.unique_authors == 5
+
+    def test_risk_count_properties(self):
+        """Test risk count properties."""
+        result = RepositoryResult(
+            repository_path="/test/repo",
+            files=[
+                {"risk_level": "critical"},
+                {"risk_level": "critical"},
+                {"risk_level": "high"},
+                {"risk_level": "high"},
+                {"risk_level": "medium"},
+                {"risk_level": "low"}
+            ]
+        )
+
+        assert result.high_risk_count == 2
+        assert result.medium_risk_count == 1
+        assert result.low_risk_count == 1
+
+    def test_to_dict(self):
+        """Test to_dict serialization."""
+        result = RepositoryResult(
+            repository_path="/test/repo",
+            files_analyzed=10,
+            total_commits=50,
+            unique_authors=3
+        )
+
+        result_dict = result.to_dict()
+
+        assert result_dict["repository"] == "/test/repo"
+        assert result_dict["files_analyzed"] == 10
+        assert "analyzed_at" in result_dict