added configuration property 'pattern'

which corresponds to the rspec options --pattern

jruby-gradle-rspec-plugin/src/main/groovy/com/github/jrubygradle/rspec/JRubyUtils.groovy

@@ -39,7 +39,7 @@ public class JRubyUtils {
         GemUtils.setupJars(config, gemDir, GemUtils.OverwriteAction.OVERWRITE)
     }
 
-    public void exec(String... arguments) {
+    public void exec(List<String> arguments) {
         project.javaexec {
             classpath jrubyCompleteJar.absolutePath
             // JRuby looks on the classpath inside the 'bin' directory

jruby-gradle-rspec-plugin/src/main/groovy/com/github/jrubygradle/rspec/RSpec.groovy

@@ -22,6 +22,9 @@ class RSpec extends DefaultTask {
     @Input
     String version = DEFAULT_VERSION
 
+    @Input
+    String pattern
+
     @Input
     String jrubyVersion = project.jruby.defaultVersion
 
@@ -29,6 +32,10 @@ class RSpec extends DefaultTask {
         this.version = version
     }
 
+    void pattern(String files) {
+        this.pattern = files
+    }
+
     void jrubyVersion(String version) {
         this.jrubyVersion = version
     }
@@ -50,6 +57,10 @@ class RSpec extends DefaultTask {
 
         jruby.setupGemsAndJars()
 
-        jruby.exec('-S', 'rspec')
+        List<String> args = ['-S', 'rspec']
+        if (pattern != null) {
+            args += ['--pattern', pattern]
+        }
+        jruby.exec(args)
     }
 }

jruby-gradle-rspec-plugin/src/test/groovy/com/github/jrubygradle/rspec/JRubyRSpecPluginSpec.groovy

@@ -198,7 +198,7 @@ class JRubyRSpecPluginSpec extends Specification {
                 task.run()
             }
         expect:
-            output.contains( '2 examples, 0 failures' )
+            output.contains( '1 example, 0 failures' )
     }
 
     def "Run custom rspec version separate from other tasks"() {
@@ -221,4 +221,25 @@ class JRubyRSpecPluginSpec extends Specification {
             outputOther.contains( '1 example, 0 failures' )
             output.contains( '4 examples, 0 failures' )
     }
+
+    def "Run rspec with custom pattern"() {
+        given:
+            File specsDir = new File(project.projectDir, 'myspec').getAbsoluteFile()
+            Files.createSymbolicLink(specsDir.toPath(), new File('src/test/resources/simple/spec').getAbsoluteFile().toPath())
+            Task task = project.tasks.create('other', RSpec)
+            task.configure {
+                pattern 'myspec/*_spec.rb'
+            }
+            project.evaluate()
+            String outputOther = captureStdout {
+                task.run()
+            }
+            specsDir.delete()
+            String output = captureStdout {
+                project.tasks.getByName('rspec').run()
+            }
+        expect:
+            output.contains( '0 examples, 0 failures' )
+            outputOther.contains( '4 examples, 0 failures' )
+    }
 }