diff --git a/.github/workflows/unit.yml b/.github/workflows/unit.yml
new file mode 100644
index 00000000..b0977437
--- /dev/null
+++ b/.github/workflows/unit.yml
@@ -0,0 +1,42 @@
+on: [push, pull_request]
+
+
+jobs:
+  unit:
+    strategy:
+      matrix:
+        os: [ "ubuntu", "windows", "macos" ]
+        go: [ "1.14", "1.15" ]
+    runs-on: ${{ matrix.os }}-latest
+    name: Unit tests (${{ matrix.os}}, Go ${{ matrix.go }})
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-go@v2.1.1
+        with: 
+          go-version: ${{ matrix.go }}
+      - run: go version
+      - name: Install test tools
+        run: |
+          go get golang.org/x/tools/cmd/cover
+          go get github.com/onsi/ginkgo/ginkgo
+          go get github.com/onsi/gomega
+      - name: Install dependencies
+        run: go build
+      - name: Run tests
+        env:
+          TIMESCALE_FACTOR: 10
+        run: ginkgo -r -v -cover -randomizeAllSpecs -randomizeSuites -trace -skipPackage integrationtests,benchmark
+      - name: Run tests with race detector
+        if: ${{ matrix.os == 'ubuntu' }} # speed things up. Windows and OSX VMs are slow
+        env:
+          TIMESCALE_FACTOR: 20
+        run: ginkgo -r -v -race -randomizeAllSpecs -randomizeSuites -trace -skipPackage integrationtests,benchmark
+      - name: Gather coverage reports
+        if: ${{ matrix.os != 'windows' }} # TODO: figure out how to upload windows logs
+        run: cat `find . -name "*.coverprofile"` > coverage.txt
+      - name: Upload coverage to Codecov
+        if: ${{ matrix.os != 'windows' }} # TODO: figure out how to upload windows logs
+        uses: codecov/codecov-action@v1
+        with:
+          file: ./coverage.txt
+          env_vars: OS=${{ matrix.os }}, GO=${{ matrix.go }}
diff --git a/.travis.yml b/.travis.yml
index 41f2e094..ef63eb87 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -31,7 +31,3 @@ before_install:
 
 script:
   - .travis/script.sh
-
-
-after_success:
-  - .travis/after_success.sh
diff --git a/.travis/after_success.sh b/.travis/after_success.sh
deleted file mode 100755
index a453e26f..00000000
--- a/.travis/after_success.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/usr/bin/env bash
-
-set -ex
-
-if [ ${TESTMODE} == "unit" ]; then
-  cat `find . -name "*.coverprofile"` > coverage.txt
-  bash <(curl -s https://codecov.io/bash) -f coverage.txt
-fi
diff --git a/.travis/script.sh b/.travis/script.sh
index 0bfc9503..f9501fbd 100755
--- a/.travis/script.sh
+++ b/.travis/script.sh
@@ -3,12 +3,7 @@
 set -ex
 
 if [ "${TESTMODE}" == "unit" ]; then
-  ginkgo -r -v -cover -randomizeAllSpecs -randomizeSuites -trace -skipPackage integrationtests,benchmark
-  # run unit tests with the Go race detector
-  # The Go race detector only works on amd64.
-  if [ "${TRAVIS_GOARCH}" == 'amd64' ]; then
-    ginkgo -race -r -v -randomizeAllSpecs -randomizeSuites -trace -skipPackage integrationtests,benchmark
-  fi
+  ginkgo -r -v -randomizeAllSpecs -randomizeSuites -trace -skipPackage integrationtests,benchmark
 fi
 
 if [ "${TESTMODE}" == "integration" ]; then
diff --git a/appveyor.yml b/appveyor.yml
deleted file mode 100644
index d5ce4451..00000000
--- a/appveyor.yml
+++ /dev/null
@@ -1,34 +0,0 @@
-version: "{build}"
-
-os: Windows Server 2012 R2
-
-environment:
-  GOPATH: c:\gopath
-  CGO_ENABLED: 0
-  TIMESCALE_FACTOR: 40
-  matrix:
-    - GOARCH: 386
-    - GOARCH: amd64
-
-clone_folder: c:\gopath\src\github.com\lucas-clemente\quic-go
-
-install:
-  - rmdir c:\go /s /q
-  - appveyor-retry appveyor DownloadFile https://storage.googleapis.com/golang/go1.14.windows-amd64.zip
-  - 7z x go1.14.windows-amd64.zip -y -oC:\ > NUL
-  - set PATH=%PATH%;%GOPATH%\bin\windows_%GOARCH%;%GOPATH%\bin
-  - set GO111MODULE=on
-  - echo %PATH%
-  - echo %GOPATH%
-  - appveyor-retry go get github.com/onsi/ginkgo/ginkgo
-  - appveyor-retry go get github.com/onsi/gomega
-  - go version
-  - go env
-
-build_script:
-  - ginkgo -r -v -randomizeAllSpecs -randomizeSuites -trace -skipPackage benchmark,integrationtests
-  - ginkgo -randomizeAllSpecs -randomizeSuites -trace benchmark -- -size=10
-
-test: off
-
-deploy: off
diff --git a/internal/flowcontrol/base_flow_controller_test.go b/internal/flowcontrol/base_flow_controller_test.go
index 8e20072d..9971d778 100644
--- a/internal/flowcontrol/base_flow_controller_test.go
+++ b/internal/flowcontrol/base_flow_controller_test.go
@@ -155,7 +155,7 @@ var _ = Describe("Base Flow controller", func() {
 
 			It("increases the window size if read so fast that the window would be consumed in less than 4 RTTs", func() {
 				bytesRead := controller.bytesRead
-				rtt := scaleDuration(20 * time.Millisecond)
+				rtt := scaleDuration(50 * time.Millisecond)
 				setRtt(rtt)
 				// consume more than 2/3 of the window...
 				dataRead := receiveWindowSize*2/3 + 1
diff --git a/server_test.go b/server_test.go
index c22136f0..b866c393 100644
--- a/server_test.go
+++ b/server_test.go
@@ -653,10 +653,10 @@ var _ = Describe("Server", func() {
 					<-acceptSession
 					atomic.AddUint32(&counter, 1)
 					sess := NewMockQuicSession(mockCtrl)
-					sess.EXPECT().handlePacket(gomock.Any())
-					sess.EXPECT().run()
-					sess.EXPECT().Context().Return(context.Background())
-					sess.EXPECT().HandshakeComplete().Return(context.Background())
+					sess.EXPECT().handlePacket(gomock.Any()).MaxTimes(1)
+					sess.EXPECT().run().MaxTimes(1)
+					sess.EXPECT().Context().Return(context.Background()).MaxTimes(1)
+					sess.EXPECT().HandshakeComplete().Return(context.Background()).MaxTimes(1)
 					return sess
 				}