diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
new file mode 100644
index 0000000..f01b673
--- /dev/null
+++ b/.devcontainer/Dockerfile
@@ -0,0 +1,3 @@
+FROM julia:1.10
+
+RUN apt-get update && apt-get install -y git
diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
new file mode 100644
index 0000000..1410550
--- /dev/null
+++ b/.devcontainer/devcontainer.json
@@ -0,0 +1,15 @@
+{
+  "customizations": {
+      "vscode": {
+          "extensions": [
+            "julialang.language-julia",
+            "ms-azuretools.vscode-docker"
+          ]
+      }
+  },
+  "runArgs": [
+      "--privileged"
+  ],
+  "dockerFile": "Dockerfile",
+  "updateContentCommand": "julia -e 'using Pkg; Pkg.develop(path=\".\");'"
+}
diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 35a34d1..b8354d8 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -5,6 +5,7 @@ on:
       - main
     tags: '*'
   pull_request:
+  workflow_dispatch:
 concurrency:
   # Skip intermediate builds: always.
   # Cancel intermediate builds: only if it is a pull request build.
diff --git a/test/episodes.jl b/test/episodes.jl
index ef7855c..7c297d5 100644
--- a/test/episodes.jl
+++ b/test/episodes.jl
@@ -116,7 +116,8 @@ using Test
         @test eb.sampleable_inds == [1,1,1,1,1,0,0]
         @test eb[:action][6] == 6
         @test eb[:next_action][5] == 6
-        @test eb[6][:reward] == 0 #6 is not a valid index, the reward there is dummy, filled as zero
+        @test eb[:reward][6] == 0 #6 is not a valid index, the reward there is dummy, filled as zero
+        @test_throws BoundsError eb[6]  #6 is not a valid index, the reward there is dummy, filled as zero
         ep2_len = 0
         for (j,i) = enumerate(8:11)
             ep2_len += 1
diff --git a/test/traces.jl b/test/traces.jl
index f30b311..26ba16c 100644
--- a/test/traces.jl
+++ b/test/traces.jl
@@ -167,8 +167,10 @@ end
     @test t1[:reward][1] == 5
 
     @test size(Base.getindex(t1, :reward)) == (1,)
-    @test size(Base.getindex(t1, 1).state) == (2,3)
 
+    push!(t1, Val(:state), ones(2,3))
+
+    @test t1[:state][1] == ones(2,3)
 
     t2 = Traces(; a=[2, 3], b=[false, true])
     push!(t2, Val(:a), 5)