ENH: Bring back 'properties' opening check.

tests/support/assertStringContains.m

@@ -1,5 +1,4 @@
-
 function assertStringContains(text, subtext)
   assert(~isempty(strfind(text, subtext)), ...
-    'String ''%s'' should contain ''%s'', but it doesn''t.');
+    'String ''%s'' should contain ''%s'', but it doesn''t.', text, subtext);
 end

tests/test_MOcovMFile_recognizes_classdef_syntax.m

@@ -89,9 +89,16 @@
     mfile = MOcovMFile(tempfile);
     lines = get_lines(mfile);
     executable_lines = get_lines_executable(mfile);
-    properties_lines = [3, 6];
+    properties_opening = [2, 5];
+    properties_body = [3, 6];
 
-    for n = properties_lines
+    for n = properties_opening
+      assertStringContains(lines{n}, 'properties');
+      assert(~executable_lines(n), ...
+          '`%s` line is wrongly classified as executable', lines{n});
+    end
+
+    for n = properties_body;
       assertStringContains(lines{n}, 'Prop;');
       assert(~executable_lines(n), ...
           '`%s` line is wrongly classified as executable', lines{n});