HQD-588: add a unit tree for request rate (RPS) prices

res/units-tree.php

@@ -346,4 +346,14 @@
     'parent' => 'power',
     'factor' => 1000,
   ),
+  'rps' =>
+  array (
+    'parent' => '',
+    'factor' => 1,
+  ),
+  'krps' =>
+  array (
+    'parent' => 'rps',
+    'factor' => 1000,
+  ),
 );

res/units-tree.yml

@@ -74,3 +74,6 @@ power:
     W:  1
     kw: 1000
     kW: 1000
+
+rps:
+    krps: 1000

tests/unit/UnitTest.php

@@ -41,6 +41,9 @@ protected function setUp(): void
 
         $this->usd  = Unit::usd();
         $this->eur  = Unit::eur();
+
+        $this->rps  = Unit::rps();
+        $this->krps = Unit::krps();
     }
 
     public function testSame()
@@ -106,6 +109,14 @@ public function testConvertThroughRoot()
         $this->assertConvert(1000, $this->mb, $this->gb);
     }
 
+    public function testConvertFractional()
+    {
+        // assertConvert() only compares integer factors; a request rate price is
+        // often fractional once converted to its billing unit (1500 rps = 1.5 krps).
+        $this->assertSame(1.5, $this->rps->convert($this->krps, 1500));
+        $this->assertSame(1500.0, $this->krps->convert($this->rps, 1.5));
+    }
+
     public function testUnknownUnit()
     {
         $unknown = Unit::create('unknown');

tests/unit/UnitsTreeConsistencyTest.php

@@ -0,0 +1,44 @@
+<?php
+/**
+ * PHP Units of Measure Library
+ *
+ * @link      https://github.com/hiqdev/php-units
+ * @package   php-units
+ * @license   BSD-3-Clause
+ * @copyright Copyright (c) 2017-2018, HiQDev (http://hiqdev.com/)
+ */
+
+namespace hiqdev\php\units\tests;
+
+use Symfony\Component\Yaml\Yaml;
+
+/**
+ * There is no generator for units-tree.php: it is hand-maintained alongside
+ * units-tree.yml. This test ensures the two never drift apart.
+ */
+class UnitsTreeConsistencyTest extends \PHPUnit\Framework\TestCase
+{
+    private const YML_PATH = __DIR__ . '/../../res/units-tree.yml';
+    private const PHP_PATH = __DIR__ . '/../../res/units-tree.php';
+
+    public function testPhpTreeMatchesYamlTree(): void
+    {
+        $yaml = Yaml::parseFile(self::YML_PATH);
+        $php = require self::PHP_PATH;
+
+        $expected = [];
+        foreach ($yaml as $root => $children) {
+            // Every yaml root is also a directly usable unit, with itself as parent.
+            $expected[$root] = ['parent' => '', 'factor' => 1];
+            foreach ($children as $name => $factor) {
+                $expected[$name] = ['parent' => $root, 'factor' => $factor];
+            }
+        }
+
+        ksort($expected);
+        $actual = $php;
+        ksort($actual);
+
+        $this->assertSame($expected, $actual, 'units-tree.yml and units-tree.php are out of sync; there is no generator, so both must be edited by hand.');
+    }
+}