diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
new file mode 100644
index 0000000..0a950bd
--- /dev/null
+++ b/.github/workflows/main.yml
@@ -0,0 +1,23 @@
+name: main
+on:
+  pull_request:
+  push:
+    branches:
+    - master
+    tags:
+    - v*
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
+    - uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe
+    - run: go test ./...
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
+    - uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe
+    - uses: golangci/golangci-lint-action@3a919529898de77ec3da873e3063ca4b10e7f5cc
+      with:
+        version: v1.55.2
diff --git a/.golangci.yml b/.golangci.yml
new file mode 100644
index 0000000..b996a3e
--- /dev/null
+++ b/.golangci.yml
@@ -0,0 +1,140 @@
+linters:
+  enable:
+  - asasalint
+  - asciicheck
+  - bidichk
+  - bodyclose
+  - containedctx
+  - contextcheck
+  - decorder
+  - dogsled
+  - dupl
+  - dupword
+  - durationcheck
+  - errcheck
+  - errchkjson
+  - errname
+  - errorlint
+  - execinquery
+  - exhaustive
+  - exportloopref
+  - forbidigo
+  - forcetypeassert
+  - gci
+  - ginkgolinter
+  - gocheckcompilerdirectives
+  - gochecknoinits
+  - gochecksumtype
+  - gocognit
+  - goconst
+  - gocritic
+  - gocyclo
+  - godot
+  - goerr113
+  - gofmt
+  - gofumpt
+  - goheader
+  - goimports
+  - gomoddirectives
+  - gomodguard
+  - goprintffuncname
+  - gosec
+  - gosimple
+  - gosmopolitan
+  - govet
+  - grouper
+  - importas
+  - inamedparam
+  - ineffassign
+  - interfacebloat
+  - ireturn
+  - lll
+  - loggercheck
+  - makezero
+  - mirror
+  - misspell
+  - musttag
+  - nakedret
+  - nestif
+  - nilerr
+  - nilnil
+  - noctx
+  - nolintlint
+  - nonamedreturns
+  - nosprintfhostport
+  - perfsprint
+  - prealloc
+  - predeclared
+  - promlinter
+  - protogetter
+  - reassign
+  - revive
+  - rowserrcheck
+  - sloglint
+  - sqlclosecheck
+  - staticcheck
+  - stylecheck
+  - tagalign
+  - tagliatelle
+  - tenv
+  - testableexamples
+  - testifylint
+  - thelper
+  - tparallel
+  - typecheck
+  - unconvert
+  - unparam
+  - unused
+  - usestdlibvars
+  - wastedassign
+  - whitespace
+  disable:
+  - cyclop
+  - depguard
+  - exhaustruct
+  - funlen
+  - gochecknoglobals
+  - godox
+  - gomnd
+  - maintidx
+  - nlreturn
+  - paralleltest
+  - testpackage
+  - varnamelen
+  - wrapcheck
+  - wsl
+
+linters-settings:
+  gci:
+    sections:
+    - standard
+    - default
+    - prefix(github.com/chezmoi/templatefuncs)
+  gofumpt:
+    extra-rules: true
+  goimports:
+    local-prefixes: github.com/chezmoi/templatefuncs
+  govet:
+    disable:
+    - fieldalignment
+    - shadow
+    enable-all: true
+  misspell:
+    locale: US
+  stylecheck:
+    checks:
+    - all
+
+issues:
+  exclude-rules:
+  - linters:
+    - dupl
+    - scopelint
+    path: "_test\\.go"
+  - linters:
+    - forbidigo
+    - gosec
+    path: "internal/"
+  - linters:
+    - goerr113
+    text: do not define dynamic errors, use wrapped static errors instead
diff --git a/go.mod b/go.mod
index d395147..a0c7eba 100644
--- a/go.mod
+++ b/go.mod
@@ -2,10 +2,9 @@ module github.com/chezmoi/templatefuncs
 
 go 1.19
 
-require github.com/stretchr/testify v1.8.1
+require github.com/alecthomas/assert/v2 v2.4.0
 
 require (
-	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/pmezard/go-difflib v1.0.0 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
+	github.com/alecthomas/repr v0.3.0 // indirect
+	github.com/hexops/gotextdiff v1.0.3 // indirect
 )
diff --git a/go.sum b/go.sum
index 2ec90f7..bb218ed 100644
--- a/go.sum
+++ b/go.sum
@@ -1,17 +1,6 @@
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
-github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
-github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
-github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
-github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
-github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
-github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
-gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+github.com/alecthomas/assert/v2 v2.4.0 h1:/ZiZ0NnriAWPYYO+4eOjgzNELrFQLaHNr92mHSHFj9U=
+github.com/alecthomas/assert/v2 v2.4.0/go.mod h1:fw5suVxB+wfYJ3291t0hRTqtGzFYdSwstnRQdaQx2DM=
+github.com/alecthomas/repr v0.3.0 h1:NeYzUPfjjlqHY4KtzgKJiWd6sVq2eNUPTi34PiFGjY8=
+github.com/alecthomas/repr v0.3.0/go.mod h1:Fr0507jx4eOXV7AlPV6AVZLYrLIuIeSOWtW57eE/O/4=
+github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUqJM=
+github.com/hexops/gotextdiff v1.0.3/go.mod h1:pSWU5MAI3yDq+fZBTazCSJysOMbxWL1BSow5/V2vxeg=
diff --git a/templatefuncs.go b/templatefuncs.go
index b13f29e..f0fec16 100644
--- a/templatefuncs.go
+++ b/templatefuncs.go
@@ -166,7 +166,7 @@ func toStringTemplateFunc(arg any) string {
 	case float32:
 		return strconv.FormatFloat(float64(arg), 'f', -1, 32)
 	case float64:
-		return strconv.FormatFloat(float64(arg), 'f', -1, 64)
+		return strconv.FormatFloat(arg, 'f', -1, 64)
 	case int:
 		return strconv.Itoa(arg)
 	case int32:
diff --git a/templatefuncs_test.go b/templatefuncs_test.go
index ff77d8c..72029dd 100644
--- a/templatefuncs_test.go
+++ b/templatefuncs_test.go
@@ -6,8 +6,7 @@ import (
 	"testing"
 	"text/template"
 
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
+	"github.com/alecthomas/assert/v2"
 )
 
 func TestEachString(t *testing.T) {
@@ -138,11 +137,11 @@ func TestFuncMap(t *testing.T) {
 	} {
 		t.Run(strconv.Itoa(i), func(t *testing.T) {
 			tmpl, err := template.New("").Funcs(funcMap).Parse(tc.template)
-			require.NoError(t, err)
-			require.NotNil(t, tmpl)
+			assert.NoError(t, err)
+			assert.NotZero(t, tmpl)
 
 			var actual strings.Builder
-			require.NoError(t, tmpl.Execute(&actual, tc.data))
+			assert.NoError(t, tmpl.Execute(&actual, tc.data))
 			assert.Equal(t, tc.expected, actual.String())
 		})
 	}