diff --git a/.github/workflows/codeformat-pr.yml b/.github/workflows/codeformat-pr.yml
new file mode 100644
index 0000000..b6b9e05
--- /dev/null
+++ b/.github/workflows/codeformat-pr.yml
@@ -0,0 +1,29 @@
+name: Code Formatting
+
+on:
+  pull_request:
+    branches:
+      - master
+    types: [opened, edited, reopened, synchronize]
+
+jobs:
+  format:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          ref: ${{ github.head_ref }}
+      - uses: julia-actions/setup-julia@v1
+        with:
+          version: 1.6
+      - name: Install JuliaFormatter and format
+        run: julia -e 'import Pkg; Pkg.add("JuliaFormatter"); using JuliaFormatter; format(".")'
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v3
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          commit-message: Format files using JuliaFormatter
+          title: ${{ format('[AUTO] Format {0} using JuliaFormatter', github.event.pull_request.number) }}
+          body: ${{ format('[JuliaFormatter.jl](https://github.com/domluna/JuliaFormatter.jl) would suggest these formatting changes against \#{0}.', github.event.pull_request.number) }}
+          labels: no changelog
+          branch: ${{ format('code-format/{0}', github.event.pull_request.number) }}
diff --git a/test/runtests.jl b/test/runtests.jl
index 3248921..7f0cd19 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -23,3 +23,23 @@ using Random
         end
     end
 end
+
+@testset "zero bins" begin
+    h = SingleThreadFixedWidth2DHistogram()
+    calc_hist!(h, rand(UInt8, 10, 10), rand(UInt8, 10, 10))
+
+    @test any(counts(h) .!= 0)
+
+    zero!(h)
+    @test all(counts(h) .== 0)
+end
+
+@testset "default hist bin type" begin
+    h = SingleThreadFixedWidth2DHistogram()
+    @test bin_type(h) == UInt8
+end
+
+@testset "custom hist bin type" begin
+    h = SingleThreadFixedWidth2DHistogram(Int32(0), Int32(16), 16)
+    @test bin_type(h) == Int32
+end