diff --git a/htmlSanityCheck-cli/build.gradle b/htmlSanityCheck-cli/build.gradle
index 24a43f93..5d16e1f3 100644
--- a/htmlSanityCheck-cli/build.gradle
+++ b/htmlSanityCheck-cli/build.gradle
@@ -2,6 +2,10 @@ plugins {
     id 'application'
 }
 
+test {
+    useJUnitPlatform()
+}
+
 dependencies {
     implementation libs.picocli.impl
     annotationProcessor libs.picocli.annotationprocessor
@@ -11,6 +15,12 @@ dependencies {
     implementation libs.groovy.all
 
     implementation project(":htmlSanityCheck-core")
+
+    testImplementation 'org.spockframework:spock-core:2.3-groovy-3.0'
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.10.1'
+    testImplementation 'org.mockito:mockito-junit-jupiter:3.11.2'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.10.1'
+    testImplementation( "com.athaydes:spock-reports:2.5.0-groovy-3.0" )
 }
 
 compileGroovy {
diff --git a/htmlSanityCheck-cli/src/main/groovy/org/aim42/htmlsanitycheck/cli/Main.groovy b/htmlSanityCheck-cli/src/main/groovy/org/aim42/htmlsanitycheck/cli/Main.groovy
index 9e983acf..7bce1074 100644
--- a/htmlSanityCheck-cli/src/main/groovy/org/aim42/htmlsanitycheck/cli/Main.groovy
+++ b/htmlSanityCheck-cli/src/main/groovy/org/aim42/htmlsanitycheck/cli/Main.groovy
@@ -22,6 +22,16 @@ import java.nio.file.Paths
 class Main implements Runnable {
     private static final Logger logger = LoggerFactory.getLogger(Main.class)
 
+    MainRunner runner
+
+    Main() {
+        Main(new MainRunner())
+    }
+
+    Main(MainRunner runner) {
+        this.runner = runner
+    }
+
     @Option(names = ["-r", "--resultsDir"], description = "Results Directory")
     String resultsDirectoryName = "/tmp/results"
 
@@ -38,7 +48,7 @@ class Main implements Runnable {
     File[] srcDocs
 
     static void main(String[] args) {
-        Main app = new Main()
+        Main app = new Main(new MainRunner())
         CommandLine cmd = new CommandLine(app)
         cmd.execute(args)
     }
@@ -52,38 +62,44 @@ class Main implements Runnable {
                 .collect { it.toFile() }
     }
 
-    void run() {
-        var configuration = new Configuration()
+    static class MainRunner {
+        void run() {
+            var configuration = new Configuration()
 
-        configuration.addConfigurationItem(Configuration.ITEM_NAME_sourceDir, srcDir)
+            configuration.addConfigurationItem(Configuration.ITEM_NAME_sourceDir, srcDir)
 
-        def srcDocuments = srcDocs ?: findFiles()
-        if (!srcDocuments) {
-            CommandLine cmd = new CommandLine(this)
-            System.err.println("Please specify at least one src document (either explicitly or implicitly)")
-            cmd.usage(System.out)
-            System.exit(1)
-        }
-        configuration.addConfigurationItem(Configuration.ITEM_NAME_sourceDocuments, srcDocuments)
+            def srcDocuments = srcDocs ?: findFiles()
+            if (!srcDocuments) {
+                CommandLine cmd = new CommandLine(this)
+                System.err.println("Please specify at least one src document (either explicitly or implicitly)")
+                cmd.usage(System.out)
+                System.exit(1)
+            }
+            configuration.addConfigurationItem(Configuration.ITEM_NAME_sourceDocuments, srcDocuments)
 
-        var resultsDirectory = new File(resultsDirectoryName)
-        configuration.addConfigurationItem((Configuration.ITEM_NAME_checkingResultsDir), resultsDirectory)
+            var resultsDirectory = new File(resultsDirectoryName)
+            configuration.addConfigurationItem((Configuration.ITEM_NAME_checkingResultsDir), resultsDirectory)
 
-        if (configuration.isValid()) {
-            // create output directory for checking results
-            resultsDirectory.mkdirs()
+            if (configuration.isValid()) {
+                // create output directory for checking results
+                resultsDirectory.mkdirs()
 
-            // create an AllChecksRunner...
-            var allChecksRunner = new AllChecksRunner(configuration)
+                // create an AllChecksRunner...
+                var allChecksRunner = new AllChecksRunner(configuration)
 
-            // ... and perform the actual checks
-            var allChecks = allChecksRunner.performAllChecks()
+                // ... and perform the actual checks
+                var allChecks = allChecksRunner.performAllChecks()
 
-            // check for findings and fail build if requested
-            var nrOfFindingsOnAllPages = allChecks.nrOfFindingsOnAllPages()
-            logger.debug("Found ${nrOfFindingsOnAllPages} error(s) on all checked pages")
+                // check for findings and fail build if requested
+                var nrOfFindingsOnAllPages = allChecks.nrOfFindingsOnAllPages()
+                logger.debug("Found ${nrOfFindingsOnAllPages} error(s) on all checked pages")
+            }
         }
     }
+
+    void run() {
+        runner.run()
+    }
 }
 
 /*========================================================================
diff --git a/htmlSanityCheck-cli/src/test/groovy/org/aim42/htmlsanitycheck/cli/MainCliSpec.groovy b/htmlSanityCheck-cli/src/test/groovy/org/aim42/htmlsanitycheck/cli/MainCliSpec.groovy
new file mode 100644
index 00000000..96ae0f69
--- /dev/null
+++ b/htmlSanityCheck-cli/src/test/groovy/org/aim42/htmlsanitycheck/cli/MainCliSpec.groovy
@@ -0,0 +1,35 @@
+package org.aim42.htmlsanitycheck.cli
+
+
+import picocli.CommandLine
+import spock.lang.Specification
+import spock.lang.Unroll
+
+class MainCliSpec extends Specification {
+
+    Main.MainRunner myAppRunner = Mock(Main.MainRunner)
+
+    @Unroll
+    def "test hsc with #args"() {
+        given:
+        def cmdLine = new CommandLine(new Main(myAppRunner))
+
+        when:
+        def exitCode = cmdLine.execute(args.split())
+
+        then:
+        exitCode == expectedExitCode
+        (runnerWasCalled ? 1 : 0) * myAppRunner.run()
+
+        where:
+        args                         | expectedExitCode | runnerWasCalled
+        "-h"                         | 0                | false
+        "--help"                     | 0                | false
+        "-V"                         | 0                | false
+        "--version"                  | 0                | false
+        ""                           | 0                | true
+        "."                          | 0                | true
+        "-r /tmp/results"            | 0                | true
+        "--resultsDir /tmp/results"  | 0                | true
+    }
+}