diff --git a/.travis.yml b/.travis.yml
index d96224e..cde6eb2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -20,13 +20,11 @@ before_script:
   - ./cc-test-reporter before-build
 
 install:
-  - wget https://github.com/go-task/task/releases/download/v2.5.0/task_linux_amd64.tar.gz
-  - tar xf task_linux_amd64.tar.gz
-  - mv task $HOME/gopath/bin
+  - curl -sL https://taskfile.dev/install.sh | sh
 
 script:
-  - diff -u <(echo -n) <(task lint)
-  - task test-coverage
+  - diff -u <(echo -n) <(./bin/task lint)
+  - ./bin/task test-coverage
 
 after_script:
   - ./cc-test-reporter after-build --exit-code $TRAVIS_TEST_RESULT
diff --git a/Gopkg.lock b/Gopkg.lock
deleted file mode 100644
index d527288..0000000
--- a/Gopkg.lock
+++ /dev/null
@@ -1,39 +0,0 @@
-# This file is autogenerated, do not edit; changes may be undone by the next 'dep ensure'.
-
-
-[[projects]]
-  digest = "1:ffe9824d294da03b391f44e1ae8281281b4afc1bdaa9588c9097785e3af10cec"
-  name = "github.com/davecgh/go-spew"
-  packages = ["spew"]
-  pruneopts = "NUT"
-  revision = "8991bc29aa16c548c550c7ff78260e27b9ab7c73"
-  version = "v1.1.1"
-
-[[projects]]
-  digest = "1:0028cb19b2e4c3112225cd871870f2d9cf49b9b4276531f03438a88e94be86fe"
-  name = "github.com/pmezard/go-difflib"
-  packages = ["difflib"]
-  pruneopts = "NUT"
-  revision = "792786c7400a136282c1664665ae0a8db921c6c2"
-  version = "v1.0.0"
-
-[[projects]]
-  digest = "1:0331452965d8695c0a5633e0f509012987681a654f388f2ad0c3b2d7f7004b1c"
-  name = "github.com/stretchr/testify"
-  packages = [
-    "assert",
-    "require",
-  ]
-  pruneopts = "NUT"
-  revision = "f35b8ab0b5a2cef36673838d662e249dd9c94686"
-  version = "v1.2.2"
-
-[solve-meta]
-  analyzer-name = "dep"
-  analyzer-version = 1
-  input-imports = [
-    "github.com/stretchr/testify/assert",
-    "github.com/stretchr/testify/require",
-  ]
-  solver-name = "gps-cdcl"
-  solver-version = 1
diff --git a/Gopkg.toml b/Gopkg.toml
deleted file mode 100644
index d70f157..0000000
--- a/Gopkg.toml
+++ /dev/null
@@ -1,8 +0,0 @@
-[prune]
-  unused-packages = true
-  non-go = true
-  go-tests = true
-
-[[constraint]]
-  name = "github.com/stretchr/testify"
-  version = "~1.2.0"
diff --git a/README.md b/README.md
index fb1618c..246660b 100644
--- a/README.md
+++ b/README.md
@@ -74,7 +74,7 @@ To update Objx to the latest version, run:
     go get -u github.com/stretchr/objx
 
 ### Supported go versions
-We support the lastest three major Go versions, which are 1.9, 1.10 and 1.11 at the moment.
+We support the lastest three major Go versions, which are 1.10, 1.11 and 1.12 at the moment.
 
 ## Contributing
 Please feel free to submit issues, fork the repository and send pull requests!
diff --git a/Taskfile.yml b/Taskfile.yml
index a3c5223..a749ac5 100644
--- a/Taskfile.yml
+++ b/Taskfile.yml
@@ -1,30 +1,30 @@
-default:
-  deps: [test]
+version: '2'
 
-update-deps:
-  desc: Updates dependencies
-  cmds:
-    - dep ensure
-    - dep ensure -update
+env:
+  GOFLAGS: -mod=vendor
 
-lint:
-  desc: Checks code style
-  cmds:
-    - gofmt -d -s *.go
-    - go vet .
-  silent: true
+tasks:
+  default:
+    deps: [test]
 
-lint-fix:
-  desc: Fixes code style
-  cmds:
-    - gofmt -w -s *.go
+  lint:
+    desc: Checks code style
+    cmds:
+      - gofmt -d -s *.go
+      - go vet ./...
+    silent: true
 
-test:
-  desc: Runs go tests
-  cmds:
-    - go test -race  .
+  lint-fix:
+    desc: Fixes code style
+    cmds:
+      - gofmt -w -s *.go
 
-test-coverage:
-  desc: Runs go tests and calucates test coverage
-  cmds:
-    - go test -coverprofile=c.out .
+  test:
+    desc: Runs go tests
+    cmds:
+      - go test -race  ./...
+
+  test-coverage:
+    desc: Runs go tests and calucates test coverage
+    cmds:
+      - go test -race -coverprofile=c.out ./...
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..31ec5a7
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,8 @@
+module github.com/stretchr/objx
+
+go 1.12
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/stretchr/testify v1.3.0
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..4f89841
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,8 @@
+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/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
diff --git a/vendor/github.com/stretchr/testify/LICENSE b/vendor/github.com/stretchr/testify/LICENSE
index 473b670..f38ec59 100644
--- a/vendor/github.com/stretchr/testify/LICENSE
+++ b/vendor/github.com/stretchr/testify/LICENSE
@@ -1,22 +1,21 @@
-Copyright (c) 2012 - 2013 Mat Ryer and Tyler Bunnell
+MIT License
 
-Please consider promoting this project if you find it useful.
+Copyright (c) 2012-2018 Mat Ryer and Tyler Bunnell
 
-Permission is hereby granted, free of charge, to any person 
-obtaining a copy of this software and associated documentation 
-files (the "Software"), to deal in the Software without restriction, 
-including without limitation the rights to use, copy, modify, merge, 
-publish, distribute, sublicense, and/or sell copies of the Software, 
-and to permit persons to whom the Software is furnished to do so, 
-subject to the following conditions:
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
 
-The above copyright notice and this permission notice shall be included
-in all copies or substantial portions of the Software.
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 
-OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
-IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
-DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT 
-OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE 
-OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/vendor/github.com/stretchr/testify/assert/assertion_format.go.tmpl b/vendor/github.com/stretchr/testify/assert/assertion_format.go.tmpl
new file mode 100644
index 0000000..d2bb0b8
--- /dev/null
+++ b/vendor/github.com/stretchr/testify/assert/assertion_format.go.tmpl
@@ -0,0 +1,5 @@
+{{.CommentFormat}}
+func {{.DocInfo.Name}}f(t TestingT, {{.ParamsFormat}}) bool {
+	if h, ok := t.(tHelper); ok { h.Helper() }
+	return {{.DocInfo.Name}}(t, {{.ForwardedParamsFormat}})
+}
diff --git a/vendor/github.com/stretchr/testify/assert/assertion_forward.go.tmpl b/vendor/github.com/stretchr/testify/assert/assertion_forward.go.tmpl
new file mode 100644
index 0000000..188bb9e
--- /dev/null
+++ b/vendor/github.com/stretchr/testify/assert/assertion_forward.go.tmpl
@@ -0,0 +1,5 @@
+{{.CommentWithoutT "a"}}
+func (a *Assertions) {{.DocInfo.Name}}({{.Params}}) bool {
+	if h, ok := a.t.(tHelper); ok { h.Helper() }
+	return {{.DocInfo.Name}}(a.t, {{.ForwardedParams}})
+}
diff --git a/vendor/github.com/stretchr/testify/assert/assertions.go b/vendor/github.com/stretchr/testify/assert/assertions.go
index 5bdec56..9bd4a80 100644
--- a/vendor/github.com/stretchr/testify/assert/assertions.go
+++ b/vendor/github.com/stretchr/testify/assert/assertions.go
@@ -39,7 +39,7 @@ type ValueAssertionFunc func(TestingT, interface{}, ...interface{}) bool
 // for table driven tests.
 type BoolAssertionFunc func(TestingT, bool, ...interface{}) bool
 
-// ValuesAssertionFunc is a common function prototype when validating an error value.  Can be useful
+// ErrorAssertionFunc is a common function prototype when validating an error value.  Can be useful
 // for table driven tests.
 type ErrorAssertionFunc func(TestingT, error, ...interface{}) bool
 
@@ -179,7 +179,11 @@ func messageFromMsgAndArgs(msgAndArgs ...interface{}) string {
 		return ""
 	}
 	if len(msgAndArgs) == 1 {
-		return msgAndArgs[0].(string)
+		msg := msgAndArgs[0]
+		if msgAsStr, ok := msg.(string); ok {
+			return msgAsStr
+		}
+		return fmt.Sprintf("%+v", msg)
 	}
 	if len(msgAndArgs) > 1 {
 		return fmt.Sprintf(msgAndArgs[0].(string), msgAndArgs[1:]...)
@@ -415,6 +419,17 @@ func NotNil(t TestingT, object interface{}, msgAndArgs ...interface{}) bool {
 	return Fail(t, "Expected value not to be nil.", msgAndArgs...)
 }
 
+// containsKind checks if a specified kind in the slice of kinds.
+func containsKind(kinds []reflect.Kind, kind reflect.Kind) bool {
+	for i := 0; i < len(kinds); i++ {
+		if kind == kinds[i] {
+			return true
+		}
+	}
+
+	return false
+}
+
 // isNil checks if a specified object is nil or not, without Failing.
 func isNil(object interface{}) bool {
 	if object == nil {
@@ -423,7 +438,14 @@ func isNil(object interface{}) bool {
 
 	value := reflect.ValueOf(object)
 	kind := value.Kind()
-	if kind >= reflect.Chan && kind <= reflect.Slice && value.IsNil() {
+	isNilableKind := containsKind(
+		[]reflect.Kind{
+			reflect.Chan, reflect.Func,
+			reflect.Interface, reflect.Map,
+			reflect.Ptr, reflect.Slice},
+		kind)
+
+	if isNilableKind && value.IsNil() {
 		return true
 	}
 
@@ -1327,7 +1349,7 @@ func typeAndKind(v interface{}) (reflect.Type, reflect.Kind) {
 }
 
 // diff returns a diff of both values as long as both are of the same type and
-// are a struct, map, slice or array. Otherwise it returns an empty string.
+// are a struct, map, slice, array or string. Otherwise it returns an empty string.
 func diff(expected interface{}, actual interface{}) string {
 	if expected == nil || actual == nil {
 		return ""
@@ -1345,7 +1367,7 @@ func diff(expected interface{}, actual interface{}) string {
 	}
 
 	var e, a string
-	if ek != reflect.String {
+	if et != reflect.TypeOf("") {
 		e = spewConfig.Sdump(expected)
 		a = spewConfig.Sdump(actual)
 	} else {
diff --git a/vendor/github.com/stretchr/testify/require/require.go.tmpl b/vendor/github.com/stretchr/testify/require/require.go.tmpl
new file mode 100644
index 0000000..6ffc751
--- /dev/null
+++ b/vendor/github.com/stretchr/testify/require/require.go.tmpl
@@ -0,0 +1,6 @@
+{{.Comment}}
+func {{.DocInfo.Name}}(t TestingT, {{.Params}}) {
+	if assert.{{.DocInfo.Name}}(t, {{.ForwardedParams}}) { return }
+	if h, ok := t.(tHelper); ok { h.Helper() }
+	t.FailNow()
+}
diff --git a/vendor/github.com/stretchr/testify/require/require_forward.go.tmpl b/vendor/github.com/stretchr/testify/require/require_forward.go.tmpl
new file mode 100644
index 0000000..54124df
--- /dev/null
+++ b/vendor/github.com/stretchr/testify/require/require_forward.go.tmpl
@@ -0,0 +1,5 @@
+{{.CommentWithoutT "a"}}
+func (a *Assertions) {{.DocInfo.Name}}({{.Params}}) {
+	if h, ok := a.t.(tHelper); ok { h.Helper() }
+	{{.DocInfo.Name}}(a.t, {{.ForwardedParams}})
+}
diff --git a/vendor/github.com/stretchr/testify/require/requirements.go b/vendor/github.com/stretchr/testify/require/requirements.go
index 690583a..6b85c5e 100644
--- a/vendor/github.com/stretchr/testify/require/requirements.go
+++ b/vendor/github.com/stretchr/testify/require/requirements.go
@@ -22,7 +22,7 @@ type ValueAssertionFunc func(TestingT, interface{}, ...interface{})
 // for table driven tests.
 type BoolAssertionFunc func(TestingT, bool, ...interface{})
 
-// ValuesAssertionFunc is a common function prototype when validating an error value.  Can be useful
+// ErrorAssertionFunc is a common function prototype when validating an error value.  Can be useful
 // for table driven tests.
 type ErrorAssertionFunc func(TestingT, error, ...interface{})
 
diff --git a/vendor/modules.txt b/vendor/modules.txt
new file mode 100644
index 0000000..e176afb
--- /dev/null
+++ b/vendor/modules.txt
@@ -0,0 +1,7 @@
+# github.com/davecgh/go-spew v1.1.1
+github.com/davecgh/go-spew/spew
+# github.com/pmezard/go-difflib v1.0.0
+github.com/pmezard/go-difflib/difflib
+# github.com/stretchr/testify v1.3.0
+github.com/stretchr/testify/assert
+github.com/stretchr/testify/require