Add PHPUnit as a dev dependency

.gitignore

@@ -1,3 +1,8 @@
+# Test files
 tests/tests-config.php
 tests/report*
-tests/run-tests.log
+tests/run-tests.log
+
+# Dependencies
+vendor
+composer.lock

composer.json

@@ -15,12 +15,20 @@
         "issues": "https://github.com/brianlmoon/net_gearman/issues"
     },
     "require": {
-        "php": ">=5.6.0"
+        "php": "^7.0.0"
     },
     "autoload": {
         "classmap": [ "Net/Gearman" ]
     },
+    "autoload-dev": {
+        "psr-4": {
+            "Net\\Gearman\\Tests\\": "tests/"
+        }
+    },
     "include-path": [
         "."
-    ]
+    ],
+    "require-dev": {
+        "phpunit/phpunit": "^7.3"
+    }
 }

phpunit.xml.dist

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit bootstrap="./tests/bootstrap.php"
+         colors="true">
+    <testsuites>
+        <testsuite name="Main">
+            <directory suffix="Test.php">./tests</directory>
+        </testsuite>
+    </testsuites>
+    <groups>
+        <exclude>
+            <group>functional</group>
+        </exclude>
+    </groups>
+    <filter>
+        <whitelist>
+            <directory>./Net</directory>
+        </whitelist>
+    </filter>
+</phpunit>

tests/bootstrap.php

@@ -0,0 +1,25 @@
+<?php
+
+require __DIR__ . '/../vendor/autoload.php';
+
+/**
+ * Function for helping debug tests since modern PHP Unit
+ * does not allow var_dump to send output to STDOUT.
+ */
+function _debug() {
+    $bt = debug_backtrace();
+    fwrite(STDERR, "\nSTART DEBUG\n");
+    foreach ($bt as $pos => $t) {
+        if (!isset($t["file"])) {
+            break;
+        }
+        fwrite(STDERR, "#$pos {$t["file"]} on line {$t["line"]}\n");
+    }
+    fwrite(STDERR, "###########\n");
+    $args = func_get_args();
+    foreach ($args as $arg) {
+        fwrite(STDERR, trim(var_export($arg, true))."\n");
+    }
+    fwrite(STDERR, "###########\n");
+    fwrite(STDERR, "END DEBUG\n\n");
+}