Php unit10 (#124)

* Static PHPUnit providers
* Limit PHP upgrades till new PHP version is tested
* Upgrade PHPUnit config schema

.gitignore

@@ -1,6 +1,7 @@
 vendor/
 .idea/
 composer.lock
+.phpunit.cache
 .phpunit.result.cache
 .vscode
 .php-cs-fixer.cache

composer.json

@@ -28,7 +28,7 @@
 
   },
   "require": {
-    "php": ">=8.0"
+    "php": ">=8.0 <8.3"
   },
   "require-dev": {
     "phpunit/phpunit": ">=9.0",

phpunit.xml.dist

@@ -1,20 +1,14 @@
 <?xml version="1.0" encoding="UTF-8"?>
-
-<phpunit backupGlobals="false"
-         backupStaticAttributes="false"
-         colors="true"
-         convertErrorsToExceptions="true"
-         convertNoticesToExceptions="true"
-         convertWarningsToExceptions="true"
-         convertDeprecationsToExceptions="true"
-         processIsolation="false"
-         stopOnFailure="false"
-         bootstrap="./tests/bootstrap.php"
-        >
-
-    <testsuites>
-        <testsuite name="Math Executor tests">
-            <directory>./tests/</directory>
-        </testsuite>
-    </testsuites>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  backupGlobals="false"
+  colors="true"
+  processIsolation="false"
+  stopOnFailure="false"
+  bootstrap="./tests/bootstrap.php"
+  xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.0/phpunit.xsd">
+  <testsuites>
+    <testsuite name="Math Executor tests">
+      <directory>./tests/</directory>
+    </testsuite>
+  </testsuites>
 </phpunit>

tests/MathTest.php

@@ -51,7 +51,7 @@ class MathTest extends TestCase
      *
      * @return array<array<string>>
      */
-    public function providerExpressions()
+    public static function providerExpressions()
     {
         return [
           ['-5'],
@@ -295,7 +295,7 @@ class MathTest extends TestCase
      *
      * @return array<array<string>>
      */
-    public function bcMathExpressions()
+    public static function bcMathExpressions()
     {
         return [
           ['-5'],
@@ -518,7 +518,7 @@ class MathTest extends TestCase
      *
      * @return array<array<string>>
      */
-    public function incorrectExpressions()
+    public static function incorrectExpressions()
     {
         return [
           ['1 * + '],
@@ -1091,7 +1091,7 @@ class MathTest extends TestCase
      *
      * @return array<array<mixed>>
      */
-    public function providerExpressionValues()
+    public static function providerExpressionValues()
     {
         return [
           ['arccos(0.5)', \acos(0.5)],