New rule: Lint/BadDirective (#143)

* New rule: Lint/BadDirective

* Address PR feedback

spec/ameba/rule/lint/bad_directive_spec.cr

@@ -0,0 +1,66 @@
+require "../../../spec_helper"
+
+module Ameba::Rule::Lint
+  describe BadDirective do
+    subject = BadDirective.new
+
+    it "does not report if rule is correct" do
+      s = Source.new %(
+        # ameba:disable Lint/BadDirective
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it "reports if there is incorrect action" do
+      s = Source.new %(
+        # ameba:foo Lint/BadDirective
+      ), "source.cr"
+      subject.catch(s).should_not be_valid
+      s.issues.size.should eq 1
+
+      issue = s.issues.first
+      issue.message.should eq(
+        "Bad action in comment directive: 'foo'. Possible values: disable, enable"
+      )
+      issue.location.to_s.should eq "source.cr:1:1"
+      issue.end_location.to_s.should eq ""
+    end
+
+    it "reports if there are incorrect rule names" do
+      s = Source.new %(
+        # ameba:enable BadRule1,BadRule2
+      ), "source.cr"
+      subject.catch(s).should_not be_valid
+      s.issues.size.should eq 1
+
+      issue = s.issues.first
+      issue.message.should eq(
+        "Such rules do not exist: BadRule1, BadRule2"
+      )
+      issue.location.to_s.should eq "source.cr:1:1"
+      issue.end_location.to_s.should eq ""
+    end
+
+    it "does not report if there no action and rules at all" do
+      s = Source.new %(
+        # ameba:
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it "does not report if there are no rules" do
+      s = Source.new %(
+        # ameba:enable
+        # ameba:disable
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it "does not report if there are group names in the directive" do
+      s = Source.new %(
+        # ameba:disable Style Performance
+      )
+      subject.catch(s).should be_valid
+    end
+  end
+end