diff --git a/.github/workflows/pythontests.yml b/.github/workflows/pythontests.yml
index facad41..0f2965d 100644
--- a/.github/workflows/pythontests.yml
+++ b/.github/workflows/pythontests.yml
@@ -20,20 +20,15 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v1
+      uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip
-        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
-        python -m pip install -e .[test]
+      run: python -m pip install -e .[test,boost,root]
     - name: Install optional dependencies for tests
-      run: |
-        pip install boost-histogram uproot awkward pandas || true
+      run: pip install pandas
     - name: Run tests
-      run: |
-        python -m pytest -s tests/test.py
+      run: python -m pytest -s
     - name: Run CLI
       run: |
         histoprint tests/data/1D.txt
diff --git a/histoprint/formatter.py b/histoprint/formatter.py
index 72d223c..0de94c5 100644
--- a/histoprint/formatter.py
+++ b/histoprint/formatter.py
@@ -1,12 +1,14 @@
 """Module for plotting Numpy-like 1D histograms to the terminal."""
 
 import shutil
+from collections.abc import Sequence
 from itertools import cycle
 from typing import Optional
 
 import click
 import numpy as np
 from uhi.numpy_plottable import ensure_plottable_histogram
+from uhi.typing.plottable import PlottableHistogram
 
 DEFAULT_SYMBOLS = " |=/\\"
 COMPOSING_SYMBOLS = "/\\"
@@ -560,12 +562,23 @@ def get_plottable_protocol_bin_edges(axis):
 def get_count_edges(hist):
     """Get bin contents and edges from a compatible histogram."""
 
-    # Make sure we have a PlottableProtocol histogram
-    hist = ensure_plottable_histogram(hist)
+    # Support sequence of histograms
+    if isinstance(hist, Sequence) and isinstance(hist[0], PlottableHistogram):
+        count = np.stack([h.values() for h in hist])
+        edges = get_plottable_protocol_bin_edges(hist[0].axes[0])
+        for other_edges in (
+            get_plottable_protocol_bin_edges(h.axes[0]) for h in hist[1:]
+        ):
+            np.testing.assert_allclose(edges, other_edges)
+
+    else:
+        # Single histogram or (a,b,c, edges) tuple:
+        # Make sure we have a PlottableProtocol histogram
+        hist = ensure_plottable_histogram(hist)
 
-    # Use the PlottableProtocol
-    count = hist.values()
-    edges = get_plottable_protocol_bin_edges(hist.axes[0])
+        # Use the PlottableProtocol
+        count = hist.values()
+        edges = get_plottable_protocol_bin_edges(hist.axes[0])
 
     return count, edges
 
diff --git a/noxfile.py b/noxfile.py
new file mode 100644
index 0000000..36a95d1
--- /dev/null
+++ b/noxfile.py
@@ -0,0 +1,35 @@
+from __future__ import annotations
+
+import nox
+
+ALL_PYTHONS = ["3.6", "3.7", "3.8", "3.9"]
+
+nox.options.sessions = ["lint", "tests"]
+
+
+@nox.session
+def lint(session):
+    """
+    Run the linter.
+    """
+    session.install("pre-commit")
+    session.run("pre-commit", "run", "--all-files", *session.posargs)
+
+
+@nox.session(python=ALL_PYTHONS, reuse_venv=True)
+def tests(session):
+    """
+    Run the unit and regular tests.
+    """
+    session.install(".[test,boost,root]")
+    session.run("pytest", "-s", *session.posargs)
+
+
+@nox.session
+def build(session):
+    """
+    Build an SDist and wheel.
+    """
+
+    session.install("build")
+    session.run("python", "-m", "build")
diff --git a/pyproject.toml b/pyproject.toml
index 864e347..5b740ea 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -10,12 +10,23 @@ build-backend = "setuptools.build_meta"
 [tool.setuptools_scm]
 write_to = "histoprint/version.py"
 
+[tool.pytest.ini_options]
+minversion = "6.0"
+addopts = "-ra --strict-markers --showlocals --color=yes"
+testpaths = [
+    "tests",
+]
+
 [tool.isort]
 profile = "black"
 multi_line_output = 3
 
 [tool.check-manifest]
-ignore=[".pre-commit-config.yaml", "histoprint/version.py"]
+ignore = [
+    ".pre-commit-config.yaml",
+    "histoprint/version.py",
+    "noxfile.py",
+]
 
 [tool.mypy]
 files = ["histoprint"]
diff --git a/setup.cfg b/setup.cfg
index 38612e9..77068ec 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -41,11 +41,13 @@ console_scripts =
     histoprint=histoprint.cli:histoprint
 
 [options.extras_require]
+boost =
+    boost-histogram>=1.1
 root =
     awkward>=1
     uproot>=4
 test =
-    pytest>=4.6
+    pytest>=6.0
 
 [flake8]
 ignore = E203, E231, E501, E722, W503, B950
diff --git a/tests/__init__.py b/tests/__init__.py
deleted file mode 100644
index e69de29..0000000
diff --git a/tests/test.py b/tests/test_basic.py
similarity index 59%
rename from tests/test.py
rename to tests/test_basic.py
index 07ac111..afc2ca5 100644
--- a/tests/test.py
+++ b/tests/test_basic.py
@@ -1,4 +1,8 @@
+import io
+
 import numpy as np
+import pytest
+from uhi.numpy_plottable import ensure_plottable_histogram
 
 import histoprint as hp
 
@@ -59,10 +63,7 @@ def test_nan():
 def test_boost():
     """Test boost-histogram if it is available."""
 
-    try:
-        import boost_histogram as bh
-    except ModuleNotFoundError:
-        return
+    bh = pytest.importorskip("boost_histogram")
 
     hist = bh.Histogram(bh.axis.Regular(20, -3, 3))
     hist.fill(np.random.randn(1000))
@@ -70,14 +71,10 @@ def test_boost():
 
 
 def test_uproot():
-    """Test uproot hsitograms if it is available."""
+    """Test uproot histograms if it is available."""
 
-    try:
-        # Only used to check whether modules are available
-        import awkward  # noqa: F401
-        import uproot
-    except ModuleNotFoundError:
-        return
+    pytest.importorskip("awkward")
+    uproot = pytest.importorskip("uproot")
 
     with uproot.open("tests/data/histograms.root") as F:
         hist = F["one"]
@@ -90,7 +87,34 @@ def test_uproot():
     hp.print_hist(hist, title="uproot TH1")
 
 
-if __name__ == "__main__":
-    test_hist()
-    test_boost()
-    test_uproot()
+def test_stack():
+    A = np.random.randn(1000) - 2
+    B = np.random.randn(1000)
+    C = np.random.randn(1000) + 2
+    D = np.random.randn(500) * 2
+
+    hp.text_hist(B)
+    hp.text_hist(
+        B, bins=[-5, -3, -2, -1, -0.5, 0, 0.5, 1, 2, 3, 5], title="Variable bin widths"
+    )
+
+    histA = np.histogram(A, bins=15, range=(-5, 5))
+    histB = np.histogram(B, bins=15, range=(-5, 5))
+    histC = np.histogram(C, bins=15, range=(-5, 5))
+    histD = np.histogram(D, bins=15, range=(-5, 5))
+    histAll = ([histA[0], histB[0], histC[0], histD[0]], histA[1])
+
+    hA = ensure_plottable_histogram(histA)
+    hB = ensure_plottable_histogram(histB)
+    hC = ensure_plottable_histogram(histC)
+    hD = ensure_plottable_histogram(histD)
+
+    hist_stack = [hA, hB, hC, hD]
+
+    out1 = io.StringIO()
+    out2 = io.StringIO()
+
+    hp.print_hist(histAll, file=out1, title="Overlays", labels="ABCD")
+    hp.print_hist(hist_stack, file=out2, title="Overlays", labels="ABCD")
+
+    assert out1.getvalue() == out2.getvalue()