Add additional tests

README.md

@@ -6,6 +6,17 @@
 
 Simple PHP package to convert between different units of weight measurement.
 
+Supports gram, kilogram, milligram, ounce, pound, stone and ton... and can easily be extended to add additional units.
+
+```php
+echo (new Pound(27.8))
+    ->to(Kilogram::class)
+    ->round()
+    ->formatted()
+
+// 12.6kg
+```
+
 ## Installation
 
 You can install the package via composer:
@@ -28,34 +39,35 @@ $kilograms->setAmount(5.75);
 $ounce = $kilograms->to(Ounce::class);
 
 // Get weight amount
-$ounce->getAmount();
-```
+$ounce->amount();
 
-Supported measurement units:
+// Round the amount
+// Defaults to a precision of 1 decimal place
+$ounce->round();
 
-```php
-// Gram
-\JacobFitzp\WeightConversions\Units\Gram::class;
-
-// Kilogram
-\JacobFitzp\WeightConversions\Units\Kilogram::class;
-
-// Milligram
-\JacobFitzp\WeightConversions\Units\Milligram::class;
-
-// Ounce
-\JacobFitzp\WeightConversions\Units\Ounce::class;
+// Get a formatted human-readable version of the amount
+// For example "2kgG", "12st 5" 
+$ounce->formatted();
+```
 
-// Pound
-\JacobFitzp\WeightConversions\Units\Pound::class;
+### Extending 
 
-// Stone
-\JacobFitzp\WeightConversions\Units\Stone::class;
+You can create your own units of measurement by extending the `AbstractUnit` class:
 
-// Ton
-\JacobFitzp\WeightConversions\Units\Ton::class;
+```php
+class Hobnobs extends AbstractUnit
+{
+    public const RELATIVE_TO_KG = 50;
+
+    public function formatted(string $format = '%s hobnobs'): string
+    {
+        return sprintf($format, $this->amount());
+    }
+}
 ```
 
+Let's break down how this works... The main thing to be aware of is the `RELATIVE_TO_KG` constant, this represents the amount of the unit that is relative to 1kg - For exampe, above we are saying that 50 hobnobs = 1kg. This is used as the basis for all conversion calculations.
+
 ## Testing
 
 ```bash

src/Units/AbstractUnit.php

@@ -18,20 +18,29 @@ abstract class AbstractUnit
      *
      * @var float|int
      */
-    protected float $amountInKilograms = 0;
+    public float|int $amountInKilograms = 0;
+    protected false|int $roundingPrecision = false;
 
-    public function __construct(protected float $amount = 0)
+    public function __construct(protected int|float $amount = 0)
     {
         $this->calculateAmountInKilograms();
     }
 
     /**
      * Get weight amount for this unit
      *
-     * @return float
+     * @return int|float
      */
-    public function getAmount(): float
+    public function amount(): int|float
     {
+        // With rounding
+        if (is_int($this->roundingPrecision)) {
+            return round(
+                $this->amount,
+                $this->roundingPrecision
+            );
+        }
+
         return $this->amount;
     }
 
@@ -61,6 +70,28 @@ public function to(string $unitType): AbstractUnit
         return new $unitType($unitType::RELATIVE_TO_KG * $this->amountInKilograms);
     }
 
+    /**
+     * Round the amount
+     *
+     * @param false|int $precision
+     * @return $this
+     */
+    public function round(false|int $precision = 1): AbstractUnit
+    {
+        $this->roundingPrecision = $precision;
+
+        return $this;
+    }
+
+    /**
+     * Get a formatted human-readable version of the amount
+     * For example "23KG", "12st 5"
+     *
+     * @param string $format
+     * @return string
+     */
+    abstract public function formatted(string $format = ''): string;
+
     /**
      * Calculate the amount in kilograms.
      * This is used as the basis for all conversions
@@ -69,6 +100,6 @@ public function to(string $unitType): AbstractUnit
      */
     protected function calculateAmountInKilograms(): void
     {
-        $this->amountInKilograms = self::RELATIVE_TO_KG * $this->amount;
+        $this->amountInKilograms = $this->amount() / $this::RELATIVE_TO_KG;
     }
 }

src/Units/Gram.php

@@ -5,4 +5,9 @@
 class Gram extends AbstractUnit
 {
     public const RELATIVE_TO_KG = 1000;
+
+    public function formatted(string $format = '%sg'): string
+    {
+        return sprintf($format, $this->amount());
+    }
 }

src/Units/Kilogram.php

@@ -5,4 +5,9 @@
 class Kilogram extends AbstractUnit
 {
     public const RELATIVE_TO_KG = 1;
+
+    public function formatted(string $format = '%skg'): string
+    {
+        return sprintf($format, $this->amount());
+    }
 }

src/Units/Milligram.php

@@ -5,4 +5,9 @@
 class Milligram extends AbstractUnit
 {
     public const RELATIVE_TO_KG = 1000000;
+
+    public function formatted(string $format = '%smg'): string
+    {
+        return sprintf($format, $this->amount());
+    }
 }

src/Units/Ounce.php

@@ -5,4 +5,9 @@
 class Ounce extends AbstractUnit
 {
     public const RELATIVE_TO_KG = 35.274;
+
+    public function formatted(string $format = '%soz'): string
+    {
+        return sprintf($format, $this->amount());
+    }
 }

src/Units/Pound.php

@@ -5,4 +5,9 @@
 class Pound extends AbstractUnit
 {
     public const RELATIVE_TO_KG = 2.2046;
+
+    public function formatted(string $format = '%slb'): string
+    {
+        return sprintf($format, $this->amount());
+    }
 }

src/Units/Stone.php

@@ -5,4 +5,22 @@
 class Stone extends AbstractUnit
 {
     public const RELATIVE_TO_KG = 0.15747;
+
+    /**
+     * Get formatted version which can be displayed to user
+     * For example "12st 6"
+     *
+     * @param string $format
+     * @return string
+     */
+    public function formatted(string $format = '%sst %s'): string
+    {
+        $stones = floor($this->amount());
+        $pounds = (new self($this->amount - $stones))
+            ->to(Pound::class)
+            ->round(0)
+            ->amount();
+
+        return sprintf($format, $stones, $pounds);
+    }
 }

src/Units/Ton.php

@@ -5,4 +5,9 @@
 class Ton extends AbstractUnit
 {
     public const RELATIVE_TO_KG = 0.001;
+
+    public function formatted(string $format = '%sT'): string
+    {
+        return sprintf($format, $this->amount());
+    }
 }

tests/Units/AbstractUnitTest.php

@@ -0,0 +1,70 @@
+<?php
+
+namespace JacobFitzp\WeightConversions\Tests\Units;
+
+use JacobFitzp\WeightConversions\Units\AbstractUnit;
+use JacobFitzp\WeightConversions\Units\Kilogram;
+use PHPUnit\Framework\TestCase;
+
+class AbstractUnitTest extends TestCase
+{
+    public function test_it_can_get_amount(): void
+    {
+        $hobnobs = new Hobnob(25);
+
+        $this->assertEquals(25, $hobnobs->amount());
+    }
+
+    public function test_it_can_set_amount(): void
+    {
+        $hobnobs = new Hobnob(25);
+        $hobnobs->setAmount(50);
+
+        $this->assertEquals(50, $hobnobs->amount());
+    }
+
+    public function test_it_can_convert_to_kg(): void
+    {
+        $kg = (new Hobnob(75))
+            ->to(Kilogram::class);
+
+        $this->assertInstanceOf(Kilogram::class, $kg);
+        $this->assertEquals(1.5, $kg->amount());
+    }
+
+    public function test_it_can_convert_from_kg(): void
+    {
+        $hobnobs = (new Kilogram(2))
+            ->to(Hobnob::class);
+
+        $this->assertInstanceOf(Hobnob::class, $hobnobs);
+        $this->assertEquals(100, $hobnobs->amount());
+    }
+
+    public function test_it_can_format_amount(): void
+    {
+        $hobnobs = new Hobnob(25);
+
+        $this->assertEquals('25 hobnobs', $hobnobs->formatted());
+    }
+
+    public function test_it_can_round_amount(): void
+    {
+        $hobnobs = new Hobnob(25.1234);
+
+        $this->assertEquals(25.1, $hobnobs->round()->amount());
+        $this->assertEquals(25.12, $hobnobs->round(2)->amount());
+        $this->assertEquals(25.123, $hobnobs->round(3)->amount());
+        $this->assertEquals(25.1234, $hobnobs->round(4)->amount());
+    }
+}
+
+class Hobnob extends AbstractUnit
+{
+    public const RELATIVE_TO_KG = 50;
+
+    public function formatted(string $format = '%s hobnobs'): string
+    {
+        return sprintf($format, $this->amount());
+    }
+}