Respect min/max height for flex column containers

Fix #2374.

tests/layout/test_flex.py

@@ -30,6 +30,32 @@ def test_flex_direction_row():
     assert div_1.position_x < div_2.position_x < div_3.position_x
 
 
+@assert_no_logs
+def test_flex_direction_row_max_width():
+    page, = render_pages('''
+      <article style="display: flex; max-width: 100px">
+        <div></div>
+      </article>
+    ''')
+    html, = page.children
+    body, = html.children
+    article, = body.children
+    assert article.width == 100
+
+
+@assert_no_logs
+def test_flex_direction_row_min_height():
+    page, = render_pages('''
+      <article style="display: flex; min-height: 100px">
+        <div></div>
+      </article>
+    ''')
+    html, = page.children
+    body, = html.children
+    article, = body.children
+    assert article.height == 100
+
+
 @assert_no_logs
 def test_flex_direction_row_rtl():
     page, = render_pages('''
@@ -135,6 +161,44 @@ def test_flex_direction_column():
     assert div_1.position_y < div_2.position_y < div_3.position_y
 
 
+@assert_no_logs
+def test_flex_direction_column_min_width():
+    page, = render_pages('''
+      <article style="display: flex; flex-direction: column; min-height: 100px">
+        <div></div>
+      </article>
+    ''')
+    html, = page.children
+    body, = html.children
+    article, = body.children
+    assert article.height == 100
+
+
+@assert_no_logs
+def test_flex_direction_column_max_height():
+    page, = render_pages('''
+      <article style="display: flex; flex-flow: column wrap; max-height: 100px">
+        <div style="height: 40px">A</div>
+        <div style="height: 40px">B</div>
+        <div style="height: 40px">C</div>
+      </article>
+    ''')
+    html, = page.children
+    body, = html.children
+    article, = body.children
+    assert article.height == 100
+    div1, div2, div3 = article.children
+    assert div1.height == 40
+    assert div1.position_x == 0
+    assert div1.position_y == 0
+    assert div2.height == 40
+    assert div2.position_x == 0
+    assert div2.position_y == 40
+    assert div3.height == 40
+    assert div3.position_x == div1.width
+    assert div3.position_y == 0
+
+
 @assert_no_logs
 def test_flex_direction_column_rtl():
     page, = render_pages('''

weasyprint/layout/flex.py

@@ -7,7 +7,7 @@
 from ..formatting_structure import boxes
 from . import percent
 from .absolute import AbsolutePlaceholder, absolute_layout
-from .preferred import max_content_width, min_content_width
+from .preferred import max_content_width, min_content_width, min_max
 from .table import find_in_flow_baseline
 
 
@@ -311,6 +311,7 @@ def flex_layout(context, box, bottom_space, skip_stack, containing_block,
                     children = children[:index + 1]
                     break
                 box.height += child_height
+        box.height = max(box.min_height, min(box.height, box.max_height))
 
     # 9.3.5 If the flex container is single-line, collect all the flex items
     # into a single flex line.