diff --git a/tests/run-tests.py b/tests/run-tests.py
--- a/tests/run-tests.py
+++ b/tests/run-tests.py
@@ -120,7 +120,7 @@
         }
 
     class TestRunnerLexer(lexer.RegexLexer):
-        testpattern = r'[\w-]+\.(t|py)( \(case [\w-]+\))?'
+        testpattern = r'[\w-]+\.(t|py)(#[\w-]+)?'
         tokens = {
             'root': [
                 (r'^Skipped', token.Generic.Skipped, 'skipped'),
@@ -1247,7 +1247,7 @@
         self._allcases = parsettestcases(path)
         super(TTest, self).__init__(path, *args, **kwds)
         if case:
-            self.name = '%s (case %s)' % (self.name, _strpath(case))
+            self.name = '%s#%s' % (self.name, _strpath(case))
             self.errpath = b'%s.%s.err' % (self.errpath[:-4], case)
             self._tmpname += b'-%s' % case
         self._have = {}
@@ -2646,7 +2646,7 @@
                 expanded_args.append(arg)
         args = expanded_args
 
-        testcasepattern = re.compile(r'([\w-]+\.t|py)( \(case ([\w-])+\))')
+        testcasepattern = re.compile(r'([\w-]+\.t|py)(#([\w-])+)')
         tests = []
         for t in args:
             case = None
diff --git a/tests/test-run-tests.t b/tests/test-run-tests.t
--- a/tests/test-run-tests.t
+++ b/tests/test-run-tests.t
@@ -1496,9 +1496,9 @@
      $ [ $V = C ]
    #endif
   
-  ERROR: test-cases-abc.t (case B) output changed
+  ERROR: test-cases-abc.t#B output changed
   !.
-  Failed test-cases-abc.t (case B): output changed
+  Failed test-cases-abc.t#B: output changed
   # Ran 3 tests, 0 skipped, 1 failed.
   python hash seed: * (glob)
   [1]
@@ -1519,9 +1519,9 @@
      $ [ $V = C ]
    #endif
   
-  ERROR: test-cases-abc.t (case B) output changed
+  ERROR: test-cases-abc.t#B output changed
   !.
-  Failed test-cases-abc.t (case B): output changed
+  Failed test-cases-abc.t#B: output changed
   # Ran 2 tests, 0 skipped, 1 failed.
   python hash seed: * (glob)
   [1]
@@ -1544,9 +1544,9 @@
      $ [ $V = C ]
    #endif
   
-  ERROR: test-cases-abc.t (case B) output changed
+  ERROR: test-cases-abc.t#B output changed
   !.
-  Failed test-cases-abc.t (case B): output changed
+  Failed test-cases-abc.t#B: output changed
   # Ran 2 tests, 0 skipped, 1 failed.
   python hash seed: * (glob)
   [1]
@@ -1573,7 +1573,7 @@
 
 Support running a specific test case
 
-  $ rt "test-cases-abc.t (case B)"
+  $ rt "test-cases-abc.t#B"
   
   --- $TESTTMP/anothertests/cases/test-cases-abc.t
   +++ $TESTTMP/anothertests/cases/test-cases-abc.t.B.err
@@ -1587,16 +1587,16 @@
      $ [ $V = C ]
    #endif
   
-  ERROR: test-cases-abc.t (case B) output changed
+  ERROR: test-cases-abc.t#B output changed
   !
-  Failed test-cases-abc.t (case B): output changed
+  Failed test-cases-abc.t#B: output changed
   # Ran 1 tests, 0 skipped, 1 failed.
   python hash seed: * (glob)
   [1]
 
 Support running multiple test cases in the same file
 
-  $ rt "test-cases-abc.t (case B)" "test-cases-abc.t (case C)"
+  $ rt test-cases-abc.t#B test-cases-abc.t#C
   
   --- $TESTTMP/anothertests/cases/test-cases-abc.t
   +++ $TESTTMP/anothertests/cases/test-cases-abc.t.B.err
@@ -1610,16 +1610,16 @@
      $ [ $V = C ]
    #endif
   
-  ERROR: test-cases-abc.t (case B) output changed
+  ERROR: test-cases-abc.t#B output changed
   !.
-  Failed test-cases-abc.t (case B): output changed
+  Failed test-cases-abc.t#B: output changed
   # Ran 2 tests, 0 skipped, 1 failed.
   python hash seed: * (glob)
   [1]
 
 Support running invalid test cases
 
-  $ rt "test-cases-abc.t (case B)" "test-cases-abc.t (case D)"
+  $ rt test-cases-abc.t#B test-cases-abc.t#D
   
   --- $TESTTMP/anothertests/cases/test-cases-abc.t
   +++ $TESTTMP/anothertests/cases/test-cases-abc.t.B.err
@@ -1633,9 +1633,9 @@
      $ [ $V = C ]
    #endif
   
-  ERROR: test-cases-abc.t (case B) output changed
+  ERROR: test-cases-abc.t#B output changed
   !
-  Failed test-cases-abc.t (case B): output changed
+  Failed test-cases-abc.t#B: output changed
   # Ran 1 tests, 0 skipped, 1 failed.
   python hash seed: * (glob)
   [1]