Updated CI config for Travis, preload OLE (#16)

* Test only on supported PHP versions on Travis CI.

* Preload OLE.php as contains important constants.
Were getting: Use of undefined constant OLE_PPS_TYPE_FILE - assumed 'OLE_PPS_TYPE_FILE' (this will throw an Error in a future version of PHP) in OLE/PPS/File.php:60

* Forbid installing on PHP 7.3 for time being.
pear/OLE does not really work on PHP 7.3, so this package is also unusable there.

.travis.yml

@@ -2,11 +2,11 @@ sudo: false
 
 language: php
 php:
-  - 5.3
-  - 5.4
   - 5.5
   - 5.6
+  - 7.0
   - 7.1
+  - 7.2
 
 cache:
   directories:
@@ -15,3 +15,5 @@ cache:
 install:
   - composer install --prefer-dist
 
+script:
+  - php vendor/bin/phpunit

Spreadsheet/Excel/Writer/Workbook.php

@@ -39,6 +39,10 @@ if (!class_exists('Spreadsheet_Excel_Writer_BIFFwriter')) {
     require_once 'Spreadsheet/Excel/Writer/Parser.php';
 }
 
+if (!class_exists('OLE')) {
+    require_once 'OLE.php';
+}
+
 if (!class_exists('OLE_PPS_Root')) {
     require_once 'OLE/PPS/Root.php';
 }

composer.json

@@ -51,8 +51,8 @@
     "type": "library",
     "require": {
         "pear/pear-core-minimal": "^1.10",
-        "pear/ole": "*",
-        "php": ">=5.3.3"
+        "pear/ole": ">=1.0.0RC3",
+        "php": ">=5.3.3 <7.3"
     },
     "require-dev": {
         "phpunit/phpunit": "<6.0"

test/Test/Spreadsheet/Excel/Writer/WorkbookTest.php

@@ -6,6 +6,12 @@
  */
 class Test_Spreadsheet_Excel_Writer_WorkbookTest extends Test_Spreadsheet_Excel_WriterTestCase
 {
+    public static function setUpBeforeClass()
+    {
+        // Preload constants from OLE
+        @class_exists(OLE::class);
+    }
+
     public function testSetVersion()
     {
         $workbook = $this->getNewWorkbook();