diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 242b5b5..ff5376b 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -13,9 +13,9 @@ stages:
       vmImage: ubuntu-latest
     steps:
     - task: GoTool@0
-      displayName: "Install Go 1.14"
+      displayName: "Install Go 1.15"
       inputs:
-        version: "1.14"
+        version: "1.15"
     - script: echo "##vso[task.setvariable variable=PATH]${PATH}:/home/vsts/go/bin/"
     - script: mkdir -p ${HOME}/go/src/github.com/pelletier/go-toml
     - script: cp -R . ${HOME}/go/src/github.com/pelletier/go-toml
@@ -36,9 +36,9 @@ stages:
       vmImage: ubuntu-latest
     steps:
     - task: GoTool@0
-      displayName: "Install Go 1.14"
+      displayName: "Install Go 1.15"
       inputs:
-        version: "1.14"
+        version: "1.15"
     - task: Go@0
       displayName: "go fmt ./..."
       inputs:
@@ -51,9 +51,9 @@ stages:
       vmImage: ubuntu-latest
     steps:
     - task: GoTool@0
-      displayName: "Install Go 1.14"
+      displayName: "Install Go 1.15"
       inputs:
-        version: "1.14"
+        version: "1.15"
     - task: Go@0
       displayName: "Generate coverage"
       inputs:
@@ -71,9 +71,9 @@ stages:
       vmImage: ubuntu-latest
     steps:
     - task: GoTool@0
-      displayName: "Install Go 1.14"
+      displayName: "Install Go 1.15"
       inputs:
-        version: "1.14"
+        version: "1.15"
     - script: echo "##vso[task.setvariable variable=PATH]${PATH}:/home/vsts/go/bin/"
     - task: Bash@3
       inputs:
@@ -86,9 +86,9 @@ stages:
       vmImage: ubuntu-latest
     steps:
     - task: GoTool@0
-      displayName: "Install Go 1.14"
+      displayName: "Install Go 1.15"
       inputs:
-        version: "1.14"
+        version: "1.15"
     - script: echo "##vso[task.setvariable variable=PATH]${PATH}:/home/vsts/go/bin/"
     - script: mkdir -p ${HOME}/go/src/github.com/pelletier/go-toml
     - script: cp -R . ${HOME}/go/src/github.com/pelletier/go-toml
@@ -102,6 +102,15 @@ stages:
     displayName: "unit tests"
     strategy:
       matrix:
+        linux 1.15:
+          goVersion: '1.15'
+          imageName: 'ubuntu-latest'
+        mac 1.15:
+          goVersion: '1.15'
+          imageName: 'macOS-latest'
+        windows 1.15:
+          goVersion: '1.15'
+          imageName: 'windows-latest'
         linux 1.14:
           goVersion: '1.14'
           imageName: 'ubuntu-latest'
@@ -111,15 +120,6 @@ stages:
         windows 1.14:
           goVersion: '1.14'
           imageName: 'windows-latest'
-        linux 1.13:
-          goVersion: '1.13'
-          imageName: 'ubuntu-latest'
-        mac 1.13:
-          goVersion: '1.13'
-          imageName: 'macOS-latest'
-        windows 1.13:
-          goVersion: '1.13'
-          imageName: 'windows-latest'
     pool:
       vmImage: $(imageName)
     steps:
@@ -155,7 +155,7 @@ stages:
     - task: GoTool@0
       displayName: "Install Go"
       inputs:
-        version: 1.14
+        version: 1.15
     - task: Bash@3
       inputs:
         targetType: inline
diff --git a/marshal_test.go b/marshal_test.go
index 581657a..e5f3215 100644
--- a/marshal_test.go
+++ b/marshal_test.go
@@ -2194,10 +2194,7 @@ func TestUnmarshalBadDuration(t *testing.T) {
 	result := testBadDuration{}
 	err := NewDecoder(buf).Decode(&result)
 	if err == nil {
-		t.Fatal()
-	}
-	if err.Error() != "(1, 1): Can't convert 1z(string) to time.Duration. time: unknown unit z in duration 1z" {
-		t.Fatalf("unexpected error: %s", err)
+		t.Fatal("expected bad duration error")
 	}
 }