New rule: a literal in the condition

spec/ameba/rules/literal_in_condition_spec.cr

@@ -0,0 +1,72 @@
+require "../../spec_helper"
+
+module Ameba::Rules
+  subject = LiteralInCondition.new
+
+  describe LiteralInCondition do
+    it "passes if there is not literals in conditional" do
+      s = Source.new %(
+        if a == 2
+          :ok
+        end
+
+        :ok unless b
+
+        case string
+        when "a"
+          :ok
+        when "b"
+          :ok
+        end
+
+        unless a.nil?
+          :ok
+        end
+      )
+      subject.catch(s).valid?.should be_true
+    end
+
+    it "fails if there is a predicate in if conditional" do
+      s = Source.new %(
+        if "string"
+          :ok
+        end
+      )
+      subject.catch(s).valid?.should be_false
+    end
+
+    it "fails if there is a predicate in unless conditional" do
+      s = Source.new %(
+        unless true
+          :ok
+        end
+      )
+      subject.catch(s).valid?.should be_false
+    end
+
+    it "fails if there is a predicate in case conditional" do
+      s = Source.new %(
+        case [1, 2, 3]
+        when :array
+          :ok
+        when :not_array
+          :also_ok
+        end
+      )
+      subject.catch(s).valid?.should be_false
+    end
+
+    it "reports rule, pos and message" do
+      s = Source.new %(
+        puts "hello" if true
+      )
+      subject.catch(s)
+
+      s.errors.size.should eq 1
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.pos.should eq 2
+      error.message.should eq "Literal value found in conditional"
+    end
+  end
+end