New Group class with optional sorting

src/Group.php

@@ -2,4 +2,70 @@
 
 namespace RebelCode\Atlas;
 
-class Group extends Order {}
+use RebelCode\Atlas\Expression\ColumnTerm;
+
+class Group
+{
+    public const ASC = 'ASC';
+    public const DESC = 'DESC';
+
+    protected ColumnTerm $column;
+    protected ?string $sort;
+
+    /**
+     * Constructor.
+     *
+     * @param string|ColumnTerm $column The column to sort by.
+     * @param string|null $sort The sort order.
+     */
+    public function __construct($column, ?string $sort = null)
+    {
+        $this->column = $column instanceof ColumnTerm ? $column : new ColumnTerm(null, $column);
+        $this->sort = $sort;
+    }
+
+    public function getColumn(): ColumnTerm
+    {
+        return $this->column;
+    }
+
+    public function getSort(): ?string
+    {
+        return $this->sort;
+    }
+
+    public function asc(): Group
+    {
+        return ($this->sort !== self::ASC)
+            ? new self($this->column, self::ASC)
+            : $this;
+    }
+
+    public function desc(): Group
+    {
+        return ($this->sort !== self::DESC)
+            ? new self($this->column, self::DESC)
+            : $this;
+    }
+
+    public function noSort(): Group
+    {
+        return ($this->sort !== null)
+            ? new self($this->column, null)
+            : $this;
+    }
+
+    public function dir(?string $order, string $default = self::ASC): Group
+    {
+        if ($order !== null) {
+            $order = strtoupper($order);
+            $order = ($order === self::ASC || $order === self::DESC) ? $order : $default;
+        }
+        return new self($this->column, $order);
+    }
+
+    public static function by(string $column): Group
+    {
+        return new self($column);
+    }
+}

src/Query/Traits/HasGroupByTrait.php

@@ -2,7 +2,6 @@
 
 namespace RebelCode\Atlas\Query\Traits;
 
-use InvalidArgumentException;
 use RebelCode\Atlas\Group;
 
 trait HasGroupByTrait
@@ -36,7 +35,13 @@ protected function compileGroupBy(): string
 
         $groupParts = [];
         foreach ($this->groups as $group) {
-            $groupParts[] = $group->getColumn() . ' ' . $group->getSort();
+            $col = $group->getColumn();
+            $sort = $group->getSort();
+            if ($sort === null) {
+                $groupParts[] = $col;
+            } else {
+                $groupParts[] = "$col $sort";
+            }
         }
 
         return 'GROUP BY ' . implode(', ', $groupParts);

tests/Query/SelectQueryTest.php

@@ -314,7 +314,7 @@ public function testCompileSelectGroupBy()
             new Group('baz', Group::DESC),
         ]);
 
-        $expected = 'SELECT * FROM table GROUP BY `foo` ASC, `bar` ASC, `baz` DESC';
+        $expected = 'SELECT * FROM table GROUP BY `foo`, `bar` ASC, `baz` DESC';
         $actual = $query->toSql();
 
         $this->assertEquals($expected, $actual);

tests/Query/Traits/HasGroupByTraitTest.php

@@ -29,11 +29,12 @@ public function testSetGroups()
     public function testCompile()
     {
         $mock = $this->getMockForTrait(HasGroupByTrait::class)->groupBy([
-            Group::by('foo')->asc(),
-            Group::by('bar')->desc(),
+            Group::by('foo'),
+            Group::by('bar')->asc(),
+            Group::by('baz')->desc(),
         ]);
 
-        $this->assertEquals('GROUP BY `foo` ASC, `bar` DESC', $this->expose($mock)->compileGroupBy());
+        $this->assertEquals('GROUP BY `foo`, `bar` ASC, `baz` DESC', $this->expose($mock)->compileGroupBy());
     }
 
     public function testCompileNoGroups()