diff --git a/.gitignore b/.gitignore
index 56c75ba..4b8bcc5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -61,3 +61,6 @@ catpy/
 
 # pycharm configuration
 .idea
+
+# vscode configuration
+.vscode
diff --git a/tests/test_catmath.py b/tests/test_catmath.py
index ced6358..258d3c4 100644
--- a/tests/test_catmath.py
+++ b/tests/test_catmath.py
@@ -2,18 +2,44 @@
 
 
 def test__cat_years_to_hooman_years__middle_age__succeeds():
-    assert True
+    cat_age = 5
+    human_age = catmath.cat_years_to_hooman_years(cat_age)
+    assert human_age == 25
 
 
 def test__cat_years_to_hooman_years__less_than_one_year__succeeds():
-    assert True
+    cat_age = 0.5
+    human_age = catmath.cat_years_to_hooman_years(cat_age)
+    assert human_age == (0.5 * 5)
 
 
 def test__cat_years_to_hooman_years__0__returns_0():
-    assert True
-
+    cat_age = 0
+    human_age = catmath.cat_years_to_hooman_years(cat_age)
+    assert human_age == 0
 
 # BONUS MATERIAL FOR STEP 2
 
+
 def test__is_cat_leap_year__succeeds():
     assert catmath.is_cat_leap_year(2016) is True
+
+
+def test__is_cat_leap_year__not_divisible_by_4_isnt_leap_year():
+    assert catmath.is_cat_leap_year(123) is False
+
+
+def test__is_cat_leap_year__not_divisible_by_4__isnt_leap_year():
+    assert catmath.is_cat_leap_year(1757) is False
+
+
+def test__is_cat_leap_year__divisible_by_100__isnt_leap_year():
+    assert catmath.is_cat_leap_year(1900) is False
+
+
+def test__is_cat_leap_year__centurial_leap_year__is_leap_year():
+    assert catmath.is_cat_leap_year(2000) is True
+
+
+def test__is_cat_leap_year__typical_leap_year__is_leap_year():
+    assert catmath.is_cat_leap_year(2004) is True