diff --git a/.travis.yml b/.travis.yml
index 0ccb85a..e6f2007 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -11,6 +11,7 @@ rvm:
   - 2.3
   - 2.4
   - 2.5
+  - 2.6
   - ruby-head
 
 sudo: false
diff --git a/appveyor.yml b/appveyor.yml
index 65d029a..9b0e76b 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -38,6 +38,12 @@ environment:
     - CHILDPROCESS_POSIX_SPAWN: false
       CHILDPROCESS_UNSET: should-be-unset
       RUBY_VERSION: 25-x64
+    - CHILDPROCESS_POSIX_SPAWN: true
+      CHILDPROCESS_UNSET: should-be-unset
+      RUBY_VERSION: 26-x64
+    - CHILDPROCESS_POSIX_SPAWN: false
+      CHILDPROCESS_UNSET: should-be-unset
+      RUBY_VERSION: 26-x64
 
 install:
   - set PATH=C:\Ruby%RUBY_VERSION%\bin;%PATH%