Discover and verify samples embedded in asciidoc

This change allows users to test samples embedded in Asciidoctor.

SampleDiscovery.embeddedSamples() looks within all .adoc and
.asciidoc files for blocks marked with the .testable-sample role
and extracts source blocks with a file name to a temp directory,
then extracts a terminal command beginning with "$ " and its
output and verifies that the given sources + command produce the
given output, with normalization of course.

This is one solution for issue #2.

build.gradle.kts

@@ -1,14 +1,10 @@
 plugins {
     `build-scan`
+    java
 }
 
-subprojects {
+allprojects {
     apply(plugin = "java-library")
-    apply(plugin = "maven-publish")
-
-    group = "org.gradle"
-    version = "0.4.2"
-
     configure<JavaPluginConvention> {
         sourceCompatibility = JavaVersion.VERSION_1_7
         targetCompatibility = JavaVersion.VERSION_1_7
@@ -20,6 +16,13 @@ subprojects {
         }
         jcenter()
     }
+}
+
+subprojects {
+    apply(plugin = "maven-publish")
+
+    group = "org.gradle"
+    version = "0.4.2"
 
     configure<PublishingExtension> {
         publications.create<MavenPublication>("mavenJava") {
@@ -42,6 +45,10 @@ subprojects {
     }
 }
 
+dependencies {
+    implementation(project(":sample-check"))
+}
+
 buildScan {
     setTermsOfServiceUrl("https://gradle.com/terms-of-service")
     setTermsOfServiceAgree("yes")
@@ -50,3 +57,5 @@ buildScan {
         tag("CI")
     }
 }
+
+java.sourceSets["test"].resources.srcDirs("docs")

buildSrc/src/main/kotlin/Dependencies.kt

@@ -1,4 +1,5 @@
 object Versions {
+    val ASCIIDOCTORJ = "1.6.0-alpha.7"
     val COMMONS_IO = "2.4"
     val COMMONS_LANG3 = "3.7"
     val JUNIT = "4.12"
@@ -9,6 +10,8 @@ object Versions {
 }
 
 object Libraries {
+    val ASCIIDOCTORJ = "org.asciidoctor:asciidoctorj:${Versions.ASCIIDOCTORJ}"
+    val ASCIIDOCTORJ_API = "org.asciidoctor:asciidoctorj-api:${Versions.ASCIIDOCTORJ}"
     val COMMONS_IO = "commons-io:commons-io:${Versions.COMMONS_IO}"
     val COMMONS_LANG3 = "org.apache.commons:commons-lang3:${Versions.COMMONS_LANG3}"
     val JUNIT = "junit:junit:${Versions.JUNIT}"