tests: add hcl task driver config parsing tests (#5314)

* drivers: add config parsing tests

Add basic tests for parsing and encoding task config.

* drivers/docker: fix some config declarations

* refactor and document config parse helpers

drivers/java/driver_test.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	ctestutil "github.com/hashicorp/nomad/client/testutil"
+	"github.com/hashicorp/nomad/helper/pluginutils/hclutils"
 	"github.com/hashicorp/nomad/helper/testlog"
 	"github.com/hashicorp/nomad/helper/uuid"
 	"github.com/hashicorp/nomad/nomad/structs"
@@ -291,3 +292,27 @@ func copyFile(src, dst string, t *testing.T) {
 		t.Fatalf("copying %v -> %v failed: %v", src, dst, err)
 	}
 }
+
+func TestConfig_ParseAllHCL(t *testing.T) {
+	cfgStr := `
+config {
+  class = "java.main"
+  class_path = "/tmp/cp"
+  jar_path = "/tmp/jar.jar"
+  jvm_options = ["-Xmx600"]
+  args = ["arg1", "arg2"]
+}`
+
+	expected := &TaskConfig{
+		Class:     "java.main",
+		ClassPath: "/tmp/cp",
+		JarPath:   "/tmp/jar.jar",
+		JvmOpts:   []string{"-Xmx600"},
+		Args:      []string{"arg1", "arg2"},
+	}
+
+	var tc *TaskConfig
+	hclutils.NewConfigParser(taskConfigSpec).ParseHCL(t, cfgStr, &tc)
+
+	require.EqualValues(t, expected, tc)
+}