Implement Sparkline renderable

tests/renderables/test_sparkline.py

@@ -0,0 +1,41 @@
+from tests.utilities.render import render
+from textual.renderables.sparkline import Sparkline
+
+GREEN = "\x1b[38;2;0;255;0m"
+RED = "\x1b[38;2;255;0;0m"
+BLENDED = "\x1b[38;2;127;127;0m"  # Color between red and green
+STOP = "\x1b[0m"
+
+
+def test_sparkline_no_data():
+    assert render(Sparkline([], width=4)) == f"{GREEN}▁▁▁▁{STOP}"
+
+
+def test_sparkline_single_datapoint():
+    assert render(Sparkline([2.5], width=4)) == f"{RED}████{STOP}"
+
+
+def test_sparkline_two_values_min_max():
+    assert render(Sparkline([2, 4], width=2)) == f"{GREEN}▁{STOP}{RED}█{STOP}"
+
+
+def test_sparkline_expand_data_to_width():
+    assert render(Sparkline([2, 4],
+                            width=4)) == f"{GREEN}▁{STOP}{GREEN}▁{STOP}{RED}█{STOP}{RED}█{STOP}"
+
+
+def test_sparkline_expand_data_to_width_non_divisible():
+    assert render(Sparkline([2, 4], width=3)) == f"{GREEN}▁{STOP}{GREEN}▁{STOP}{RED}█{STOP}"
+
+
+def test_sparkline_shrink_data_to_width():
+    assert render(Sparkline([2, 2, 4, 4, 6, 6], width=3)) == f"{GREEN}▁{STOP}{BLENDED}▄{STOP}{RED}█{STOP}"
+
+
+def test_sparkline_shrink_data_to_width_non_divisible():
+    assert render(
+        Sparkline([1, 2, 3, 4, 5], width=3, summary_func=min)) == f"{GREEN}▁{STOP}{BLENDED}▄{STOP}{RED}█{STOP}"
+
+
+def test_sparkline_color_blend():
+    assert render(Sparkline([1, 2, 3], width=3)) == f"{GREEN}▁{STOP}{BLENDED}▄{STOP}{RED}█{STOP}"