drop Go 1.16, test on 1.18, add checks

.github/workflows/test.yml

@@ -4,15 +4,20 @@ jobs:
   test:
     strategy:
       matrix:
-        go-version: [1.16.x, 1.17.x]
+        go-version: [1.17.x, 1.18.x]
         os: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     steps:
-    - name: Install Go
-      uses: actions/setup-go@v2
+    - uses: actions/setup-go@v3
       with:
         go-version: ${{ matrix.go-version }}
-    - name: Checkout code
-      uses: actions/checkout@v2
-    - name: Test
-      run: go test ./...
+    - uses: actions/checkout@v3
+    - run: go test ./...
+    - run: go test -race ./...
+
+    # Static checks from this point forward. Only run on one Go version and on
+    # Linux, since it's the fastest platform, and the tools behave the same.
+    - if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.18.x'
+      run: diff <(echo -n) <(gofmt -s -d .)
+    - if: matrix.os == 'ubuntu-latest' && matrix.go-version == '1.18.x'
+      run: go vet ./...

go.mod

@@ -1,6 +1,6 @@
 module mvdan.cc/gofumpt
 
-go 1.16
+go 1.17
 
 require (
 	github.com/frankban/quicktest v1.14.2
@@ -11,3 +11,11 @@ require (
 	golang.org/x/sys v0.0.0-20220209214540-3681064d5158
 	golang.org/x/tools v0.1.9
 )
+
+require (
+	github.com/kr/pretty v0.3.0 // indirect
+	github.com/kr/text v0.2.0 // indirect
+	github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e // indirect
+	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
+	gopkg.in/errgo.v2 v2.1.0 // indirect
+)