diff --git a/OSBindings/Mac/Clock SignalTests/C1540Tests.swift b/OSBindings/Mac/Clock SignalTests/C1540Tests.swift
index a0dfd2c43..bb80f2d76 100644
--- a/OSBindings/Mac/Clock SignalTests/C1540Tests.swift	
+++ b/OSBindings/Mac/Clock SignalTests/C1540Tests.swift	
@@ -32,7 +32,7 @@ class C1540Tests: XCTestCase {
 		c1540.runForCycles(256)	// this isn't time limited on real hardware
 		XCTAssert(c1540.dataLine == true, "Listener should have let data line go high again")
 
-		for _ in 1..<8 {
+		for _ in 0..<8 {
 			// ensure the closk is true again
 			c1540.clockLine = true
 			c1540.runForCycles(40)