diff --git a/librisworks/build.gradle b/librisworks/build.gradle
index 19e68e2b54..f2e49e9cf1 100644
--- a/librisworks/build.gradle
+++ b/librisworks/build.gradle
@@ -5,6 +5,9 @@ sourceSets {
     scripts {
         groovy { srcDir 'scripts' }
     }
+    test {
+        groovy { srcDir 'src/test/groovy/' }
+    }
 }
 
 repositories {
@@ -13,10 +16,16 @@ repositories {
 
 dependencies {
     implementation project(':whelktool')
+    testImplementation project(':whelk-core')
     compileOnly "org.codehaus.groovy:groovy:${groovyVersion}"
     compileOnly project(':whelk-core')
     scriptsCompileOnly sourceSets.main.output
     scriptsCompileOnly project(':whelk-core')
+    testImplementation "org.spockframework:spock-core:${spockVersion}"
+}
+
+test {
+    useJUnitPlatform()
 }
 
 jar {
diff --git a/librisworks/src/test/groovy/se/kb/libris/mergeworks/compare/ClassificationSpec.groovy b/librisworks/src/test/groovy/se/kb/libris/mergeworks/compare/ClassificationSpec.groovy
new file mode 100644
index 0000000000..8bf21f3cfe
--- /dev/null
+++ b/librisworks/src/test/groovy/se/kb/libris/mergeworks/compare/ClassificationSpec.groovy
@@ -0,0 +1,22 @@
+package se.kb.libris.mergeworks.compare
+
+import spock.lang.Specification
+
+class ClassificationSpec extends Specification {
+    def "merge SAB codes"() {
+        expect:
+        Classification.tryMergeSabCodes(a, b) == result
+
+        where:
+        a           || b         || result
+        'H'         || 'H'       || 'H'
+        'Haaa'      || 'H'       || 'Haaa'
+        'Hcqaa'     || 'Hcbqbbb' || 'Hcqaa'
+        'Hcb'       || 'Hc'      || null
+        'Hci'       || 'Hci,u'   || 'Hci,u'
+        'Hcd.016'   || 'Hcd.01'  || 'Hcd.016'
+        'Hc.01'     || 'Hcd.01'  || 'Hcd.01'
+        'Hda.017=c' || 'Hda.018' || 'Hda.017=c'
+        'He'        || 'Hc'      || null
+    }
+}