feat(#187): add it that reveals the problem

README.md

@@ -38,7 +38,7 @@ you want to use specific (older) version of the plugin, for example `0.1.9`,
 just run the next maven command with specified version:
 
 ```shell
-mvn com.github.volodya-lombrozo:jtcop-maven-plugin:0.1.9:check
+mvn com.github.volodya-lombrozo:jtcop-maven-plugin:0.1.16:check
 ```
 
 ### Add the plugin to your `pom.xml`

pom.xml

@@ -215,7 +215,7 @@ SOFTWARE.
           <plugin>
             <groupId>com.github.volodya-lombrozo</groupId>
             <artifactId>jtcop-maven-plugin</artifactId>
-            <version>0.1.15</version>
+            <version>0.1.14</version>
             <executions>
               <execution>
                 <phase>verify</phase>

src/it/all-have-production-class/src/test/java/package-info.java

@@ -0,0 +1,29 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022-2023 Volodya
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+/**
+ * Pckage of integration tests.
+ *
+ * @since 0.1.16
+ */
+package com.github.lombrozo.testnames.it;

src/main/java/com/github/lombrozo/testnames/javaparser/JavaParserClass.java

@@ -114,7 +114,12 @@ private static Node fromCompilation(final CompilationUnit unit) {
             .filter(node -> node instanceof TypeDeclaration<?>)
             .collect(Collectors.toCollection(LinkedList::new));
         if (all.isEmpty()) {
-            throw new IllegalStateException("Compilation unit has contain at least one class");
+            throw new IllegalStateException(
+                String.format(
+                    "Compilation unit '%s' has contain at least one class",
+                    unit
+                )
+            );
         }
         return all.element();
     }