addedtest

core/slice/sort_private.odin

@@ -116,7 +116,7 @@ _stable_sort_general :: proc(data: $T/[]$E, call: $P, $KIND: Sort_Kind) {
 			left2 = first_cut
 		}
 		
-		slice.rotate_left(data[first_cut:second_cut], left - first_cut)
+		rotate_left(data[first_cut:second_cut], left - first_cut)
 		new_mid := first_cut + right2
 
 		merge(data[:new_mid], left2,      right2,       call)

tests/core/slice/test_core_slice.odin

@@ -140,6 +140,51 @@ test_sort_by_indices :: proc(t: ^testing.T) {
 	}
 }
 
+@test
+test_sort_stability :: proc(t: ^testing.T) {
+	// Test sizes are all prime.
+	test_sizes :: []int{7, 13, 347, 1031, 10111, 100003}
+    Data :: struct {
+        rand: int,
+        index: int,
+    }
+
+	for test_size in test_sizes {
+		rand.reset(t.seed)
+
+		vals  := make([]Data, test_size)
+		defer {
+			delete(vals)
+		}
+
+		// Set up test values
+		for _, i in vals {
+			vals[i].rand = rand.int_max(10)
+			vals[i].index = i
+		}
+
+		// Sort
+		slice.stable_sort_by(vals, proc(l, r: Data) -> bool {return l.rand < r.rand})
+
+		// Verify sorted test values
+		rand.reset(t.seed)
+
+        for i in 1..<len(vals) {
+            if vals[i - 1].rand < vals[i].rand {
+                continue
+            }
+            if vals[i - 1].rand > vals[i].rand {
+	            testing.expect(t, false, "Expected slice to be sorted")
+            }
+            if vals[i - 1].index > vals[i].index {
+	            testing.expect(t, false, "Expected slice to be stable")
+            }
+        }
+
+	}
+}
+
+
 @test
 test_binary_search :: proc(t: ^testing.T) {
 	index: int