Add tests for Perl and Turning detection

lib/linguist/blob_helper.rb

@@ -470,12 +470,20 @@ def guess_r_language
 
     # Internal: Guess language of .t files.
     #
-    # Makes fairly sure that it is Turing.
-    # Turing is not very popular so it would not be good to have perl users' files being confused.
-    #
     # Returns a Language.
     def guess_t_language
-      if lines.grep(/:=/).any? && lines.grep(/proc |procedure |fcn |function /).any? && lines.grep(/var/).any?
+      score = 0
+      score += 1 if lines.grep(/^% /).any?
+      score += data.gsub(/ := /).count
+      score += data.gsub(/proc |procedure |fcn |function /).count
+      score += data.gsub(/var \w+: \w+/).count
+
+      # Tell-tale signs its gotta be Perl
+      if lines.grep(/^(my )?(sub |\$|@|%)\w+/).any?
+        score = 0
+      end
+
+      if score >= 3
         Language['Turing']
       else
         Language['Perl']

test/fixtures/perl-test.t

@@ -0,0 +1,10 @@
+use strict;
+use warnings;
+
+use Foo::Bar
+
+$n = 42;
+$name = "world";
+@array = ("1","2","3");
+%hash = ("foo":"bar");
+my $name = "josh";

test/fixtures/turing.t

@@ -0,0 +1,19 @@
+% Accepts a number and calculates its factorial
+
+function factorial (n: int) : real
+    if n = 0 then
+        result 1
+    else
+        result n * factorial (n - 1)
+   end if
+end factorial
+
+var n: int
+loop
+    put "Please input an integer: " ..
+    get n
+    exit when n >= 0
+    put "Input must be a non-negative integer."
+end loop
+
+put "The factorial of ", n, " is ", factorial (n)

test/test_blob.rb

@@ -281,6 +281,10 @@ def test_language
     assert_equal Language['R'],           blob("hello-r.R").language
     assert_equal Language['Rebol'],       blob("hello-rebol.r").language
 
+    # .t disambiguation
+    assert_equal Language['Perl'],        blob("perl-test.t").language
+    assert_equal Language['Turing'],      blob("turing.t").language
+
     # ML
     assert_equal Language['OCaml'],       blob("Foo.ml").language
     assert_equal Language['Standard ML'], blob("Foo.sig").language

test/test_language.rb

@@ -20,6 +20,9 @@ def test_ambiguous_extensions
 
     assert Language.ambiguous?('.r')
     assert_equal Language['R'], Language.find_by_extension('r')
+
+    assert Language.ambiguous?('.t')
+    assert_equal Language['Perl'], Language.find_by_extension('t')
   end
 
   def test_lexer