diff --git a/.github/workflows/run_test.yml b/.github/workflows/run_test.yml
index c45bcbfc..67d0bfc7 100644
--- a/.github/workflows/run_test.yml
+++ b/.github/workflows/run_test.yml
@@ -1,4 +1,4 @@
-name: simple_calculator unit test
+name: Lab unit tests
   
 on: [push]  
   
@@ -26,7 +26,7 @@ jobs:
         continue-on-error: true  
       - name: Test with pytest  
         run: |  
-          coverage run -m pytest tests/tests_1b.py -v -s  
+          coverage run -m pytest --cov=labs tests/test_1b.py tests/test_1c.py tests/test_1d.py -v -s  
       - name: Generate Coverage Report  
         run: |  
           coverage report -m
\ No newline at end of file
diff --git a/labs/lab_1/lab_1c.py b/labs/lab_1/lab_1c.py
index 40cf98db..fd16a2f1 100644
--- a/labs/lab_1/lab_1c.py
+++ b/labs/lab_1/lab_1c.py
@@ -22,10 +22,9 @@ def max_subarray_sum(nums: list[int]) -> int:
 
     max_current = max_global = nums[0]
     
-    for num in nums:
+    for num in nums[1:]:
         max_current = max(num, max_current + num)
-        if max_current < max_global:
-            max_global = max_current
+        max_global = max(max_global, max_current)
             
     return max_global
 
diff --git a/labs/lab_1/lab_1d.py b/labs/lab_1/lab_1d.py
index ade4b4a8..1506810a 100644
--- a/labs/lab_1/lab_1d.py
+++ b/labs/lab_1/lab_1d.py
@@ -23,7 +23,7 @@ def two_sum(nums: list[int], target: int) -> list[int]:
 
     num_to_index = {}
     for index, num in enumerate(nums):
-        complement = target + num
+        complement = target - num
         if complement in num_to_index:
             return [num_to_index[complement], index]
         num_to_index[num] = index
diff --git a/tests/tests_1b.py b/tests/test_1b.py
similarity index 100%
rename from tests/tests_1b.py
rename to tests/test_1b.py
diff --git a/tests/test_1c.py b/tests/test_1c.py
new file mode 100644
index 00000000..bc8c30a4
--- /dev/null
+++ b/tests/test_1c.py
@@ -0,0 +1,27 @@
+"""
+tests_1c.py
+
+This module contains unit tests for the max_subarray_sum function defined in lab_1c.py.
+"""
+
+import pytest
+from labs.lab_1.lab_1c import max_subarray_sum
+
+def test_max_subarray_sum_positive():
+    assert max_subarray_sum([1, 2, 3, 4]) == 10  # All positive
+    assert max_subarray_sum([-2, 1, -3, 4, -1, 2, 1, -5, 4]) == 6  # Mixed, max is 4,-1,2,1
+
+def test_max_subarray_sum_negative():
+    assert max_subarray_sum([-1, -2, -3]) == -1  # All negative, max is -1
+
+def test_max_subarray_sum_single_element():
+    assert max_subarray_sum([5]) == 5
+    assert max_subarray_sum([-5]) == -5
+
+def test_max_subarray_sum_empty_list():
+    # Assuming non-empty, but test anyway
+    with pytest.raises(IndexError):
+        max_subarray_sum([])
+
+if __name__ == "__main__":
+    pytest.main()
\ No newline at end of file
diff --git a/tests/test_1d.py b/tests/test_1d.py
new file mode 100644
index 00000000..56ff72a9
--- /dev/null
+++ b/tests/test_1d.py
@@ -0,0 +1,25 @@
+"""
+tests_1d.py
+
+This module contains unit tests for the two_sum function defined in lab_1d.py.
+"""
+
+import pytest
+from labs.lab_1.lab_1d import two_sum
+
+def test_two_sum_basic():
+    assert sorted(two_sum([2, 7, 11, 15], 9)) == [0, 1]
+    assert sorted(two_sum([3, 2, 4], 6)) == [1, 2]
+
+def test_two_sum_negative():
+    assert sorted(two_sum([-1, -2, -3, -4, -5], -8)) == [2, 4]  # -3 + -5 = -8
+
+def test_two_sum_with_zero():
+    assert sorted(two_sum([0, 4, 3, 0], 0)) == [0, 3]
+
+def test_two_sum_no_solution():
+    # Though problem guarantees one, test the return
+    assert two_sum([1, 2, 3], 10) == []
+
+if __name__ == "__main__":
+    pytest.main()
\ No newline at end of file