Add addUnique function

Signed-off-by: David Arendsen <darendsen@gamepoint.com>

docs/04-functions.md

@@ -24,6 +24,7 @@ or [addRangeInBetween()](functions/addRangeInBetween.md)
 * [addReduce()](functions/addReduce.md)
 * [addSort()](functions/addSort.md)
 * [addSum()](functions/addSum.md)
+* [addUnique()](functions/addUnique.md)
 * [addUnwindow()](functions/addUnwindow.md)
 * [addWindow()](functions/addWindow.md)
 

docs/functions/addUnique.md

@@ -0,0 +1,39 @@
+# Flux Query Builder Docs
+
+## Functions » addUnique()
+
+### Parameters:
+
+<table>
+  <tbody>
+    <tr>
+      <th>Name</th>
+      <th>Required</th>
+      <th>Data type</th>
+      <th>Description</th>
+    </tr>
+    <tr>
+      <td>column</td>
+      <td>No</td>
+      <td>string</td>
+      <td>Column to search for unique values. Default is _value.</td>
+    </tr>
+  </tbody>
+</table>
+
+
+### Example
+
+```php
+->addUnique("_value")
+```
+
+This will result in the following Flux function part:
+
+```
+|> unique(column: "_value")
+```
+
+### Extra resources
+
+* [Flux documentation](https://docs.influxdata.com/flux/v0.x/stdlib/universe/unique/)

src/Builder/Universe.php

@@ -17,6 +17,7 @@ use Arendsen\FluxQueryBuilder\Functions\Min;
 use Arendsen\FluxQueryBuilder\Functions\Reduce;
 use Arendsen\FluxQueryBuilder\Functions\Sort;
 use Arendsen\FluxQueryBuilder\Functions\Sum;
+use Arendsen\FluxQueryBuilder\Functions\Unique;
 use Arendsen\FluxQueryBuilder\Functions\Window;
 
 trait Universe
@@ -133,6 +134,14 @@ trait Universe
         return $this;
     }
 
+    public function addUnique(?string $column = null): QueryBuilderInterface
+    {
+        $this->addToQuery(
+            new Unique($column)
+        );
+        return $this;
+    }
+
     public function addUnWindow(): QueryBuilderInterface
     {
         $this->addToQuery(

src/Functions/Unique.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace Arendsen\FluxQueryBuilder\Functions;
+
+use Arendsen\FluxQueryBuilder\Type;
+
+class Unique extends Base
+{
+    /**
+     * @var string|null $column
+     */
+    private $column;
+
+    public function __construct(?string $column = null)
+    {
+        $this->column = $column;
+    }
+
+    public function __toString()
+    {
+        $params = new Type(array_filter([
+          'column' => $this->column
+        ]));
+
+        return '|> unique(' . $params . ') ';
+    }
+}

tests/Functions/UniqueFunctionTest.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Functions;
+
+use Arendsen\FluxQueryBuilder\Functions\Unique;
+use PHPUnit\Framework\TestCase;
+
+final class UniqueunctionTest extends TestCase
+{
+    public function testSimpleUnique()
+    {
+        $expression = new Unique();
+
+        $query = '|> unique() ';
+
+        $this->assertEquals($query, $expression->__toString());
+    }
+
+    public function testUniqueWithColumn()
+    {
+        $expression = new Unique('something');
+
+        $query = '|> unique(column: "something") ';
+
+        $this->assertEquals($query, $expression->__toString());
+    }
+}

tests/QueryBuilderTest.php

@@ -126,6 +126,11 @@ final class QueryBuilderTest extends TestCase
                 ['something'],
                 '|> sum(column: "something") '
             ],
+            'addUnique' => [
+                'addUnique',
+                ['something'],
+                '|> unique(column: "something") '
+            ],
             'addUnwindow' => [
                 'addUnwindow',
                 [],