diff --git a/tests/test_utils_rangebar.py b/tests/test_utils_rangebar.py
new file mode 100644
index 000000000..66374a43e
--- /dev/null
+++ b/tests/test_utils_rangebar.py
@@ -0,0 +1,109 @@
+import colorama
+import pytest
+from io import StringIO
+import sys
+import os
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
+from slic.utils.rangebar import *
+
+
+@pytest.fixture
+def capture_stdout(monkeypatch):
+    buf = StringIO()
+    monkeypatch.setattr("sys.stdout", buf)
+    return buf
+
+def test_full_progress_bar(capture_stdout):
+    out = capture_stdout
+    with RangeBar(0, 100, width=10, units="kg", fmt=".0f") as bar:
+        bar.show(100)
+
+    line = out.getvalue().strip("\r\n")
+    expected = (
+        f"[ 0 kg |{colorama.Fore.GREEN}{'█' * 10}{colorama.Fore.RESET}| 100 kg ]   "
+        f"{colorama.Style.BRIGHT}100 kg{colorama.Style.RESET_ALL}"
+    )
+    assert line == expected
+
+def test_half_progress_bar(capture_stdout):
+    out = capture_stdout
+    with RangeBar(0, 100, width=10, units="kg", fmt=".0f") as bar:
+        bar.show(50)
+
+    # 5 full + 1 partial + 4 empty
+    expected_bar = f"{'█' * 5}▌{' ' * 4}"
+    line = out.getvalue().strip("\r\n")
+    expected = (
+        f"[ 0 kg |{colorama.Fore.GREEN}{expected_bar}{colorama.Fore.RESET}| 100 kg ]   "
+        f"{colorama.Style.BRIGHT}50 kg{colorama.Style.RESET_ALL}"
+    )
+    assert line == expected
+
+def test_zero_progress_bar(capture_stdout):
+    out = capture_stdout
+    with RangeBar(0, 100, width=10, units="kg", fmt=".0f") as bar:
+        bar.show(0)
+
+    # no full block, one empty partial, 9 spaces
+    expected_bar = f"{'▏'}{' ' * 9}"
+    line = out.getvalue().strip("\r\n")
+    expected = (
+        f"[ 0 kg |{colorama.Fore.GREEN}{expected_bar}{colorama.Fore.RESET}| 100 kg ]   "
+        f"{colorama.Style.BRIGHT}0 kg{colorama.Style.RESET_ALL}"
+    )
+    assert line == expected
+
+def test_overflow_bar(capture_stdout):
+    out = capture_stdout
+    with RangeBar(0, 10, width=10, fmt=".0f", units="m") as bar:
+        bar.show(15)
+
+    line = out.getvalue().strip("\r\n")
+    expected = (
+        f"[ 0 m |{colorama.Fore.RED}{'>' * 10}{colorama.Fore.RESET}| 10 m ]   "
+        f"{colorama.Style.BRIGHT}15 m{colorama.Style.RESET_ALL}"
+    )
+    assert line == expected
+
+def test_underflow_bar(capture_stdout):
+    out = capture_stdout
+    with RangeBar(0, 10, width=10, fmt=".0f", units="m") as bar:
+        bar.show(-5)
+
+    line = out.getvalue().strip("\r\n")
+    expected = (
+        f"[ 0 m |{colorama.Fore.RED}{'<' * 10}{colorama.Fore.RESET}| 10 m ]   "
+        f"{colorama.Style.BRIGHT}-5 m{colorama.Style.RESET_ALL}"
+    )
+    assert line == expected
+
+def test_repr():
+    bar = RangeBar(0, 100, width=10, units="kg", fmt=".0f")
+    expected = "[ 0 kg |10 blocks| 100 kg ]"
+    assert repr(bar) == expected
+
+def test_multiple_show_evolution(capture_stdout):
+    out = capture_stdout
+    with RangeBar(0, 100, width=10, units="kg", fmt=".0f") as bar:
+        bar.show(0)
+        bar.show(10)
+        bar.show(25)
+        bar.show(50)
+        bar.show(75)
+        bar.show(90)
+        bar.show(100)
+
+    result = out.getvalue()
+    lines = result.strip().split("\r")
+    expected_lines = [
+        f"[ 0 kg |{colorama.Fore.GREEN}{'▏'}{' ' * 9}{colorama.Fore.RESET}| 100 kg ]   {colorama.Style.BRIGHT}0 kg{colorama.Style.RESET_ALL}",
+        f"[ 0 kg |{colorama.Fore.GREEN}█{'▏'}{' ' * 8}{colorama.Fore.RESET}| 100 kg ]   {colorama.Style.BRIGHT}10 kg{colorama.Style.RESET_ALL}",
+        f"[ 0 kg |{colorama.Fore.GREEN}██▌{' ' * 7}{colorama.Fore.RESET}| 100 kg ]   {colorama.Style.BRIGHT}25 kg{colorama.Style.RESET_ALL}",
+        f"[ 0 kg |{colorama.Fore.GREEN}█████▌{' ' * 4}{colorama.Fore.RESET}| 100 kg ]   {colorama.Style.BRIGHT}50 kg{colorama.Style.RESET_ALL}",
+        f"[ 0 kg |{colorama.Fore.GREEN}███████▌▏{' '}{colorama.Fore.RESET}| 100 kg ]   {colorama.Style.BRIGHT}75 kg{colorama.Style.RESET_ALL}",
+        f"[ 0 kg |{colorama.Fore.GREEN}█████████▍{colorama.Fore.RESET}| 100 kg ]   {colorama.Style.BRIGHT}90 kg{colorama.Style.RESET_ALL}",
+        f"[ 0 kg |{colorama.Fore.GREEN}██████████{colorama.Fore.RESET}| 100 kg ]   {colorama.Style.BRIGHT}100 kg{colorama.Style.RESET_ALL}",
+    ]
+
+    for expected in expected_lines:
+        assert expected in lines