diff --git a/tests/basic/not-run.rkt b/tests/basic/not-run.rkt
index 29533de..26917b0 100644
--- a/tests/basic/not-run.rkt
+++ b/tests/basic/not-run.rkt
@@ -1,2 +1,2 @@
 #lang racket
-(if #f 1 2)
+(if #f 10 2)
diff --git a/tests/basic/not-run.rktl b/tests/basic/not-run.rktl
index 928a2a4..bbe2cc3 100644
--- a/tests/basic/not-run.rktl
+++ b/tests/basic/not-run.rktl
@@ -1 +1,2 @@
-((1 19) (21 24))
+((1 20) (24 25))
+((21 23))
diff --git a/tests/basic/prog.rktl b/tests/basic/prog.rktl
index 2f2aace..57dcaba 100644
--- a/tests/basic/prog.rktl
+++ b/tests/basic/prog.rktl
@@ -1 +1,2 @@
 ((1 21))
+()
diff --git a/tests/main.rkt b/tests/main.rkt
index ed0c21c..2776592 100644
--- a/tests/main.rkt
+++ b/tests/main.rkt
@@ -21,11 +21,18 @@
   (define coverage (get-test-coverage))
   (for ([(program cover) covered])
     (define actual-coverage (hash-ref coverage program))
-    (define expected-coverage (ranges->numbers (with-input-from-file cover read)))
+    (define-values 
+      (expected-coverage expected-uncoverage)
+      (with-input-from-file cover (lambda () (values (ranges->numbers (read))
+                                                     (ranges->numbers (read))))))
     (test-begin
      (for ([i expected-coverage])
        (check-true (covered? i actual-coverage)
                    (format "expected char ~a to be covered, but it was not, in: ~s"
+                           i program)))
+     (for ([i expected-uncoverage])
+       (check-true (not (covered? i actual-coverage))
+                   (format "expected char ~a to be uncovered, but it was, in: ~s"
                            i program)))))
 
   (clear-coverage!))
@@ -48,7 +55,7 @@
 (define (within? i src)
   (match src
     [(srcloc _ _ _ start range)
-     (>= start i (+ start range))]))
+     (<= start i (+ start range))]))
 
 (module+ test
   (define-runtime-path-list test-dirs '("basic" "simple-multi"))