added EnvironemntHelper for getting variables (#28)

src/SAREhub/Commons/Misc/EnvironmentHelper.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace SAREhub\Commons\Misc;
+
+
+class EnvironmentHelper {
+
+	public static function getVar(string $name, $default = null) {
+		$value = getenv($name);
+		return $value !== false ? $value : $default;
+	}
+
+	public static function getVars(array $schema): array {
+		$env = [];
+		foreach ($schema as $name => $default) {
+			$env[$name] = self::getVar($name, $default);
+		}
+
+		return $env;
+	}
+}

tests/SAREhub/Commons/Misc/EnvironmentHelperTest.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace SAREhub\Commons\Misc;
+
+use PHPUnit\Framework\TestCase;
+
+class EnvironmentHelperTest extends TestCase {
+
+	const VARIABLE = 'ENV_HELPER_TEST';
+
+	public function setUp() {
+		putenv(self::VARIABLE);
+	}
+
+	public function testGetVarWhenExists() {
+		putenv(self::VARIABLE.'=1');
+		$this->assertEquals(1, EnvironmentHelper::getVar(self::VARIABLE));
+	}
+
+	public function testGetVarWhenNotExists() {
+		$this->assertEquals(1, EnvironmentHelper::getVar(self::VARIABLE, 1));
+	}
+
+	public function testGetVarsWhenExists() {
+		putenv(self::VARIABLE.'=1');
+		$this->assertEquals([self::VARIABLE => 1], EnvironmentHelper::getVars([self::VARIABLE => 2]));
+	}
+
+	public function testGetVarsWhenNotExists() {
+		$this->assertEquals([self::VARIABLE => 2], EnvironmentHelper::getVars([self::VARIABLE => 2]));
+	}
+}