Add comprehensive unit tests for all endpoints: info, TVM (present-value, annuity-payment), mortgage/summary, bond/price, xirr/explain

Author: mytherapy-coding

tests/test_bond.py

@@ -72,3 +72,86 @@ def test_bond_yield_validation():
     assert response.status_code == 422
     data = response.json()
     assert data["ok"] is False
+
+
+def test_bond_price_basic():
+    """Test basic bond price calculation."""
+    payload = {
+        "face_value": 1000,
+        "coupon_rate": 0.05,
+        "years_to_maturity": 10,
+        "yield_to_maturity": 0.055,
+        "payments_per_year": 2
+    }
+    response = client.post("/v1/bond/price", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    assert data["ok"] is True
+    assert "price" in data
+    assert data["price"] > 0
+    # Bond trading at discount (YTM > coupon) should have price < face value
+    assert data["price"] < payload["face_value"]
+
+
+def test_bond_price_premium():
+    """Test bond price for premium bond (YTM < coupon rate)."""
+    payload = {
+        "face_value": 1000,
+        "coupon_rate": 0.05,
+        "years_to_maturity": 10,
+        "yield_to_maturity": 0.04,  # Lower yield = premium
+        "payments_per_year": 2
+    }
+    response = client.post("/v1/bond/price", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    assert data["ok"] is True
+    # Premium bond should have price > face value
+    assert data["price"] > payload["face_value"]
+
+
+def test_bond_price_par():
+    """Test bond price when YTM equals coupon rate (at par)."""
+    payload = {
+        "face_value": 1000,
+        "coupon_rate": 0.05,
+        "years_to_maturity": 10,
+        "yield_to_maturity": 0.05,  # Same as coupon = at par
+        "payments_per_year": 2
+    }
+    response = client.post("/v1/bond/price", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    assert data["ok"] is True
+    # At par, price should be close to face value
+    assert abs(data["price"] - payload["face_value"]) < 10
+
+
+def test_bond_price_validation_negative_face_value():
+    """Test that negative face value is rejected."""
+    payload = {
+        "face_value": -1000,
+        "coupon_rate": 0.05,
+        "years_to_maturity": 10,
+        "yield_to_maturity": 0.055,
+        "payments_per_year": 2
+    }
+    response = client.post("/v1/bond/price", json=payload)
+    assert response.status_code == 422
+    data = response.json()
+    assert data["ok"] is False
+
+
+def test_bond_price_validation_invalid_yield():
+    """Test that invalid yield (> 100%) is rejected."""
+    payload = {
+        "face_value": 1000,
+        "coupon_rate": 0.05,
+        "years_to_maturity": 10,
+        "yield_to_maturity": 1.5,  # > 100%
+        "payments_per_year": 2
+    }
+    response = client.post("/v1/bond/price", json=payload)
+    assert response.status_code == 422
+    data = response.json()
+    assert data["ok"] is False

tests/test_info.py

@@ -0,0 +1,41 @@
+"""Tests for the /v1/info endpoint."""
+from fastapi.testclient import TestClient
+from app.main import app
+
+client = TestClient(app)
+
+
+def test_info_endpoint():
+    """Test that the info endpoint returns correct metadata."""
+    response = client.get("/v1/info")
+    assert response.status_code == 200
+    data = response.json()
+    assert data["ok"] is True
+    assert data["service"] == "finance-api"
+    assert "version" in data
+    assert "environment" in data
+    assert "build_timestamp" in data
+    assert "git_sha" in data
+
+
+def test_info_response_structure():
+    """Test that the info response has the expected structure."""
+    response = client.get("/v1/info")
+    assert response.status_code == 200
+    data = response.json()
+    
+    # Check all required fields
+    required_fields = ["ok", "service", "version", "environment", "build_timestamp", "git_sha"]
+    for field in required_fields:
+        assert field in data, f"Missing field: {field}"
+    
+    # Check data types
+    assert isinstance(data["ok"], bool)
+    assert isinstance(data["service"], str)
+    assert isinstance(data["version"], str)
+    assert isinstance(data["environment"], str)
+    assert isinstance(data["build_timestamp"], str)
+    assert isinstance(data["git_sha"], str)
+    
+    # Check version format
+    assert data["version"] == "1.0.0"

tests/test_mortgage.py

@@ -276,3 +276,72 @@ def test_mortgage_with_extra_payments_structure():
     # Check date format (YYYY-MM)
     assert len(data["new_payoff_date"]) == 7
     assert data["new_payoff_date"][4] == "-"
+
+
+def test_mortgage_summary_basic():
+    """Test basic mortgage summary calculation."""
+    payload = {
+        "principal": 300000,
+        "annual_rate": 0.04,
+        "years": 30
+    }
+    response = client.post("/v1/mortgage/summary", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    assert data["ok"] is True
+    assert "monthly_payment" in data
+    assert "total_paid" in data
+    assert "total_interest" in data
+    assert "payoff_months" in data
+    assert "payoff_date" in data
+    
+    # Verify calculations
+    assert data["monthly_payment"] > 0
+    assert data["total_paid"] > data["principal"]
+    assert data["total_interest"] > 0
+    assert data["payoff_months"] == 360
+    assert data["total_paid"] == data["monthly_payment"] * data["payoff_months"]
+
+
+def test_mortgage_summary_structure():
+    """Test that mortgage summary response has all required fields."""
+    payload = {
+        "principal": 200000,
+        "annual_rate": 0.035,
+        "years": 15
+    }
+    response = client.post("/v1/mortgage/summary", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    
+    required_fields = [
+        "ok",
+        "monthly_payment",
+        "total_paid",
+        "total_interest",
+        "payoff_months",
+        "payoff_date"
+    ]
+    for field in required_fields:
+        assert field in data, f"Missing field: {field}"
+    
+    # Check date format
+    assert len(data["payoff_date"]) == 7
+    assert data["payoff_date"][4] == "-"
+
+
+def test_mortgage_summary_zero_interest():
+    """Test mortgage summary with zero interest."""
+    payload = {
+        "principal": 100000,
+        "annual_rate": 0.0,
+        "years": 10
+    }
+    response = client.post("/v1/mortgage/summary", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    
+    # With zero interest, total_interest should be 0
+    assert data["total_interest"] == 0
+    assert data["total_paid"] == payload["principal"]
+    assert data["monthly_payment"] == payload["principal"] / (payload["years"] * 12)

tests/test_tvm.py

@@ -0,0 +1,164 @@
+"""Tests for TVM (Time Value of Money) endpoints."""
+from fastapi.testclient import TestClient
+from app.main import app
+
+client = TestClient(app)
+
+
+def test_present_value_basic():
+    """Test basic present value calculation."""
+    payload = {
+        "future_value": 10000,
+        "annual_rate": 0.07,
+        "years": 10,
+        "compounds_per_year": 12
+    }
+    response = client.post("/v1/tvm/present-value", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    assert data["ok"] is True
+    assert "present_value" in data
+    assert data["present_value"] > 0
+    # Future value should be greater than present value
+    assert data["present_value"] < payload["future_value"]
+
+
+def test_present_value_zero_rate():
+    """Test present value with zero interest rate."""
+    payload = {
+        "future_value": 10000,
+        "annual_rate": 0.0,
+        "years": 10,
+        "compounds_per_year": 12
+    }
+    response = client.post("/v1/tvm/present-value", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    assert data["ok"] is True
+    # With zero rate, PV should equal FV
+    assert abs(data["present_value"] - 10000) < 0.01
+
+
+def test_present_value_validation_negative_future_value():
+    """Test that negative future value is rejected."""
+    payload = {
+        "future_value": -10000,
+        "annual_rate": 0.07,
+        "years": 10,
+        "compounds_per_year": 12
+    }
+    response = client.post("/v1/tvm/present-value", json=payload)
+    assert response.status_code == 422
+    data = response.json()
+    assert data["ok"] is False
+
+
+def test_present_value_validation_zero_years():
+    """Test that zero years is rejected."""
+    payload = {
+        "future_value": 10000,
+        "annual_rate": 0.07,
+        "years": 0,
+        "compounds_per_year": 12
+    }
+    response = client.post("/v1/tvm/present-value", json=payload)
+    assert response.status_code == 422
+    data = response.json()
+    assert data["ok"] is False
+
+
+def test_annuity_payment_basic():
+    """Test basic annuity payment calculation."""
+    payload = {
+        "present_value": 10000,
+        "annual_rate": 0.05,
+        "years": 5,
+        "payments_per_year": 12
+    }
+    response = client.post("/v1/tvm/annuity-payment", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    assert data["ok"] is True
+    assert "payment" in data
+    assert data["payment"] > 0
+    # Payment should be reasonable (less than PV per month)
+    assert data["payment"] < payload["present_value"]
+
+
+def test_annuity_payment_zero_rate():
+    """Test annuity payment with zero interest rate."""
+    payload = {
+        "present_value": 10000,
+        "annual_rate": 0.0,
+        "years": 5,
+        "payments_per_year": 12
+    }
+    response = client.post("/v1/tvm/annuity-payment", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    assert data["ok"] is True
+    # With zero rate, payment should be PV / total_payments
+    expected = 10000 / (5 * 12)
+    assert abs(data["payment"] - expected) < 0.01
+
+
+def test_annuity_payment_validation_negative_present_value():
+    """Test that negative present value is rejected."""
+    payload = {
+        "present_value": -10000,
+        "annual_rate": 0.05,
+        "years": 5,
+        "payments_per_year": 12
+    }
+    response = client.post("/v1/tvm/annuity-payment", json=payload)
+    assert response.status_code == 422
+    data = response.json()
+    assert data["ok"] is False
+
+
+def test_annuity_payment_validation_zero_payments():
+    """Test that zero payments_per_year is rejected."""
+    payload = {
+        "present_value": 10000,
+        "annual_rate": 0.05,
+        "years": 5,
+        "payments_per_year": 0
+    }
+    response = client.post("/v1/tvm/annuity-payment", json=payload)
+    assert response.status_code == 422
+    data = response.json()
+    assert data["ok"] is False
+
+
+def test_present_value_response_structure():
+    """Test that present value response has correct structure."""
+    payload = {
+        "future_value": 5000,
+        "annual_rate": 0.06,
+        "years": 5,
+        "compounds_per_year": 4
+    }
+    response = client.post("/v1/tvm/present-value", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    assert "ok" in data
+    assert "present_value" in data
+    assert isinstance(data["ok"], bool)
+    assert isinstance(data["present_value"], (int, float))
+
+
+def test_annuity_payment_response_structure():
+    """Test that annuity payment response has correct structure."""
+    payload = {
+        "present_value": 5000,
+        "annual_rate": 0.06,
+        "years": 5,
+        "payments_per_year": 4
+    }
+    response = client.post("/v1/tvm/annuity-payment", json=payload)
+    assert response.status_code == 200
+    data = response.json()
+    assert "ok" in data
+    assert "payment" in data
+    assert isinstance(data["ok"], bool)
+    assert isinstance(data["payment"], (int, float))