Add mathematical operator tags to report templates (#4443)

InvenTree/report/templatetags/report.py

@@ -184,3 +184,27 @@ def internal_link(link, text):
         return text
 
     return mark_safe(f'<a href="{url}">{text}</a>')
+
+
+@register.simple_tag()
+def add(x, y, *args, **kwargs):
+    """Add two numbers together."""
+    return x + y
+
+
+@register.simple_tag()
+def subtract(x, y):
+    """Subtract one number from another"""
+    return x - y
+
+
+@register.simple_tag()
+def multiply(x, y):
+    """Multiply two numbers together"""
+    return x * y
+
+
+@register.simple_tag()
+def divide(x, y):
+    """Divide one number by another"""
+    return x / y

InvenTree/report/tests.py

@@ -137,6 +137,14 @@ class ReportTagTest(TestCase):
             logo = report_tags.logo_image()
             self.assertIn('inventree.png', logo)
 
+    def test_maths_tags(self):
+        """Simple tests for mathematical operator tags"""
+
+        self.assertEqual(report_tags.add(1, 2), 3)
+        self.assertEqual(report_tags.subtract(10, 4.2), 5.8)
+        self.assertEqual(report_tags.multiply(2.3, 4), 9.2)
+        self.assertEqual(report_tags.divide(100, 5), 20)
+
 
 class BarcodeTagTest(TestCase):
     """Unit tests for the barcode template tags"""