Fix filenames of two function spec tests

The tests weren't being run.  Total tests increase from 2742 to 2769.

Also fix 'when using a class extending String' test.
It had been failing with...
```
RuntimeError:
       can't modify frozen AlsoString
```

1 files changed, 31 insertions, 0 deletions

diff --git a/spec/functions/length_spec.rb b/spec/functions/length_spec.rb
new file mode 100755
index 0000000..487cf21
--- /dev/null
+++ b/spec/functions/length_spec.rb
@@ -0,0 +1,31 @@
+require 'spec_helper'
+
+describe 'length' do
+  it { is_expected.not_to eq(nil) }
+  it { is_expected.to run.with_params().and_raise_error(ArgumentError, /'length' expects 1 argument, got none/) }
+  it { is_expected.to run.with_params([], 'extra').and_raise_error(ArgumentError, /'length' expects 1 argument, got 2/) }
+  it { is_expected.to run.with_params(1).and_raise_error(ArgumentError, /expects a value of type String, Array, or Hash, got Integer/) }
+  it { is_expected.to run.with_params(true).and_raise_error(ArgumentError, /expects a value of type String, Array, or Hash, got Boolean/) }
+  it { is_expected.to run.with_params('1').and_return(1) }
+  it { is_expected.to run.with_params('1.0').and_return(3) }
+  it { is_expected.to run.with_params([]).and_return(0) }
+  it { is_expected.to run.with_params(['a']).and_return(1) }
+  it { is_expected.to run.with_params(['one', 'two', 'three']).and_return(3) }
+  it { is_expected.to run.with_params(['one', 'two', 'three', 'four']).and_return(4) }
+
+  it { is_expected.to run.with_params({}).and_return(0) }
+  it { is_expected.to run.with_params({'1' => '2'}).and_return(1) }
+  it { is_expected.to run.with_params({'1' => '2', '4' => '4'}).and_return(2) }
+  it { is_expected.to run.with_params({'€' => '@', '竹' => 'ǿňè'}).and_return(2) }
+
+  it { is_expected.to run.with_params('').and_return(0) }
+  it { is_expected.to run.with_params('a').and_return(1) }
+  it { is_expected.to run.with_params('abc').and_return(3) }
+  it { is_expected.to run.with_params('abcd').and_return(4) }
+  it { is_expected.to run.with_params('万').and_return(1) }
+  it { is_expected.to run.with_params('āβćđ').and_return(4) }
+
+  context 'when using a class extending String' do
+    it { is_expected.to run.with_params(AlsoString.new('asdfghjkl')).and_return(9) }
+  end
+end