1 files changed, 32 insertions, 7 deletions
diff --git a/spec/ruby/core/string/index_spec.rb b/spec/ruby/core/string/index_spec.rb
index 8d2c8af193..3f82181b98 100644
--- a/spec/ruby/core/string/index_spec.rb
+++ b/spec/ruby/core/string/index_spec.rb
@@ -4,15 +4,15 @@ require_relative 'fixtures/classes'
 
 describe "String#index" do
   it "raises a TypeError if passed nil" do
-    -> { "abc".index nil }.should raise_error(TypeError)
+    -> { "abc".index nil }.should.raise(TypeError)
   end
 
   it "raises a TypeError if passed a boolean" do
-    -> { "abc".index true }.should raise_error(TypeError)
+    -> { "abc".index true }.should.raise(TypeError)
   end
 
   it "raises a TypeError if passed a Symbol" do
-    -> { "abc".index :a }.should raise_error(TypeError)
+    -> { "abc".index :a }.should.raise(TypeError)
   end
 
   it "calls #to_str to convert the first argument" do
@@ -28,7 +28,7 @@ describe "String#index" do
   end
 
   it "raises a TypeError if passed an Integer" do
-    -> { "abc".index 97 }.should raise_error(TypeError)
+    -> { "abc".index 97 }.should.raise(TypeError)
   end
 end
 
@@ -146,6 +146,7 @@ describe "String#index with String" do
 
   it "returns the character index after offset" do
     "われわれ".index("わ", 1).should == 2
+    "ありがとうありがとう".index("が", 3).should == 7
   end
 
   it "returns the character index after a partial first match" do
@@ -156,7 +157,22 @@ describe "String#index with String" do
     char = "れ".encode Encoding::EUC_JP
     -> do
       "あれ".index char
-    end.should raise_error(Encoding::CompatibilityError)
+    end.should.raise(Encoding::CompatibilityError)
+  end
+
+  it "handles a substring in a superset encoding" do
+    'abc'.dup.force_encoding(Encoding::US_ASCII).index('é').should == nil
+  end
+
+  it "handles a substring in a subset encoding" do
+    'été'.index('t'.dup.force_encoding(Encoding::US_ASCII)).should == 1
+  end
+
+  it "raises an Encoding::CompatibilityError if the encodings are incompatible" do
+    str = 'abc'.dup.force_encoding("ISO-2022-JP")
+    pattern = 'b'.dup.force_encoding("EUC-JP")
+
+    -> { str.index(pattern) }.should.raise(Encoding::CompatibilityError, "incompatible character encodings: ISO-2022-JP and EUC-JP")
   end
 end
 
@@ -215,6 +231,15 @@ describe "String#index with Regexp" do
     $~.should == nil
   end
 
+  it "always clear $~" do
+    "a".index(/a/)
+    $~.should_not == nil
+
+    string = "blablabla"
+    string.index(/bla/, string.length + 1)
+    $~.should == nil
+  end
+
   it "starts the search at the given offset" do
     "blablabla".index(/.{0}/, 5).should == 5
     "blablabla".index(/.{1}/, 5).should == 5
@@ -262,7 +287,7 @@ describe "String#index with Regexp" do
   end
 
   it "returns nil if the Regexp matches the empty string and the offset is out of range" do
-    "ruby".index(//,12).should be_nil
+    "ruby".index(//,12).should == nil
   end
 
   it "supports \\G which matches at the given start offset" do
@@ -307,6 +332,6 @@ describe "String#index with Regexp" do
     re = Regexp.new "れ".encode(Encoding::EUC_JP)
     -> do
       "あれ".index re
-    end.should raise_error(Encoding::CompatibilityError)
+    end.should.raise(Encoding::CompatibilityError, "incompatible encoding regexp match (EUC-JP regexp with UTF-8 string)")
   end
 end