diff --git a/prototype/DoubtTests/LocationTests.swift b/prototype/DoubtTests/LocationTests.swift
index a688212fc..01e9e7dd9 100644
--- a/prototype/DoubtTests/LocationTests.swift
+++ b/prototype/DoubtTests/LocationTests.swift
@@ -2,6 +2,10 @@ final class LocationTests: XCTestCase {
 	func testExplorationOfATermBeginsAtTheExploredTerm() {
 		assert(term.explore().it, ==, term)
 	}
+
+	func testCannotMoveUpwardsAtTheStartOfAnExploration() {
+		assert(term.explore().up?.it, ==, nil)
+	}
 }