add test cases

src/main/kotlin/com/github/roroche/plantuml/classes/ClsInPackage.kt

@@ -1,31 +1,43 @@
 package com.github.roroche.plantuml.classes
 
+import com.github.roroche.plantuml.classes.exceptions.InvalidPackageException
 import org.reflections.Reflections
 import org.reflections.scanners.SubTypesScanner
 import org.reflections.scanners.TypeAnnotationsScanner
 import org.reflections.util.ClasspathHelper
 import org.reflections.util.ConfigurationBuilder
+import java.net.URL
 import java.util.concurrent.Executors
 
 /**
  * Utility class to find [Classes] in a given package.
  *
+ * @property packageName The name of the package to scan.
+ * @property packageUrls URL of the package (passed as [Collection]).
  * @property reflections Utility to find classes in pckage.
  */
 class ClsInPackage(
+    private val packageName: String,
+    private val packageUrls: Collection<URL>,
     private val reflections: Reflections
 ) : Classes {
 
     /**
-     * Secondary constructor.
+     * Secondary constructor using URLs.
      *
      * @param packageName The name of the package to scan.
+     * @param packageUrls URL of the package (passed as [Collection]).
      */
-    constructor(packageName: String) : this(
+    constructor(
+        packageName: String,
+        packageUrls: Collection<URL>
+    ) : this(
+        packageName,
+        packageUrls,
         Reflections(
             ConfigurationBuilder()
                 .setUrls(
-                    ClasspathHelper.forPackage(packageName)
+                    packageUrls
                 ).setScanners(
                     SubTypesScanner(false),
                     TypeAnnotationsScanner()
@@ -35,10 +47,23 @@ class ClsInPackage(
         )
     )
 
+    /**
+     * Secondary constructor.
+     *
+     * @param packageName The name of the package to scan.
+     */
+    constructor(packageName: String) : this(
+        packageName,
+        ClasspathHelper.forPackage(packageName)
+    )
+
     /**
      * @return Classes to be used for diagram generation.
      */
     override fun list(): List<Class<out Any>> {
+        if (packageUrls.isNullOrEmpty()) {
+            throw InvalidPackageException(packageName)
+        }
         return reflections.getSubTypesOf(
             Any::class.java
         ).asIterable().toList()

src/main/kotlin/com/github/roroche/plantuml/classes/exceptions/InvalidPackageException.kt

@@ -0,0 +1,5 @@
+package com.github.roroche.plantuml.classes.exceptions
+
+class InvalidPackageException(
+    packageName: String
+) : RuntimeException("Invalid package '$packageName', maybe missing or empty")

src/test/kotlin/com/github/roroche/plantuml/assertions/ClsThrowsAssertion.kt

@@ -0,0 +1,31 @@
+package com.github.roroche.plantuml.assertions
+
+import com.github.roroche.plantuml.classes.Classes
+import com.pragmaticobjects.oo.tests.Assertion
+import org.assertj.core.api.Assertions.assertThatThrownBy
+
+/**
+ * Assertion that checks that [Classes] throws exception.
+ *
+ * @property classes The [Classes] to check.
+ * @property expectedClass The [Exception] [Class] expected to be thrown.
+ * @property expectedMessage The expected [Exception] message.
+ */
+class ClsThrowsAssertion(
+    private val classes: Classes,
+    private val expectedClass: Class<out Exception>,
+    private val expectedMessage: String
+) : Assertion {
+    /**
+     * Check the assertion.
+     */
+    override fun check() {
+        assertThatThrownBy {
+            classes.list()
+        }.isInstanceOf(
+            expectedClass
+        ).hasMessageContaining(
+            expectedMessage
+        )
+    }
+}

src/test/kotlin/com/github/roroche/plantuml/classes/ClsFilteredTest.kt

@@ -57,15 +57,18 @@ class ClsFilteredTest : TestsSuite(
         )
     ),
     TestCase(
-        "origin and empty filtered classes returns empty list",
-        ClsIsEmptyAssertion(
+        "origin and empty filtered classes returns concrete classes",
+        ClsContainsExactlyAssertion(
             classes = ClsFiltered(
                 origin = Classes.Simple(
                     listOf(ClsFilteredTest::class.java)
                 ),
                 ignored = Classes.Simple(
                     emptyList()
                 )
+            ),
+            expectedClasses = listOf(
+                ClsFilteredTest::class.java
             )
         )
     )

src/test/kotlin/com/github/roroche/plantuml/classes/ClsInPackageTest.kt

@@ -4,6 +4,8 @@ import com.github.roroche.examples.Car
 import com.github.roroche.examples.Driver
 import com.github.roroche.examples.Vehicle
 import com.github.roroche.plantuml.assertions.ClsContainsExactlyAssertion
+import com.github.roroche.plantuml.assertions.ClsThrowsAssertion
+import com.github.roroche.plantuml.classes.exceptions.InvalidPackageException
 import com.pragmaticobjects.oo.tests.TestCase
 import com.pragmaticobjects.oo.tests.junit5.TestsSuite
 
@@ -25,21 +27,23 @@ class ClsInPackageTest : TestsSuite(
         )
     ),
     TestCase(
-        "empty package returns empty list",
-        ClsContainsExactlyAssertion(
+        "empty package returns throws",
+        ClsThrowsAssertion(
             classes = ClsInPackage(
                 packageName = "com.github.roroche.examples.empty"
             ),
-            expectedClasses = emptyList()
+            expectedClass = InvalidPackageException::class.java,
+            expectedMessage = "Invalid package 'com.github.roroche.examples.empty', maybe missing or empty"
         )
     ),
     TestCase(
-        "not existing package returns empty list",
-        ClsContainsExactlyAssertion(
+        "not existing package throws",
+        ClsThrowsAssertion(
             classes = ClsInPackage(
                 packageName = "com.github.roroche.examples.missing"
             ),
-            expectedClasses = emptyList()
+            expectedClass = InvalidPackageException::class.java,
+            expectedMessage = "Invalid package 'com.github.roroche.examples.missing', maybe missing or empty"
         )
     )
 )