tauri-apps/tauri · error · syn::Error

unexpected value for test

Error message

unexpected value for test

What it means

The test key of #[tauri::generate_context] toggles test mode (for example, skipping asset embedding so `cargo test` stays fast). Its value must be a boolean literal (Expr::Lit with Lit::Bool); the macro explicitly pattern-matches for it. Any other value — a quoted string, an ident, a const, Some(true) — fails with 'unexpected value for test'.

Source

Thrown at crates/tauri-macros/src/context.rs:106

              } else {
                return Err(syn::Error::new(
                  input.span(),
                  "unexpected value for capabilities",
                ));
              }
            }
            "assets" => {
              assets.replace(v.value);
            }
            "test" => {
              if let Expr::Lit(ExprLit {
                lit: Lit::Bool(LitBool { value, .. }),
                ..
              }) = v.value
              {
                test = value;
              } else {
                return Err(syn::Error::new(input.span(), "unexpected value for test"));
              }
            }
            name => {
              return Err(syn::Error::new(
                input.span(),
                format!("unknown attribute {name}"),
              ));
            }
          }
        }
        Meta::List(_) => {
          return Err(syn::Error::new(input.span(), "unexpected list input"));
        }
      }

      let _ = input.parse::<Token![,]>();
    }

View on GitHub (pinned to 52e4b6e71d)

Solutions

1. Use the literal: #[tauri::generate_context(test = true)] or omit it (defaults to false)
2. For test-only behavior, gate tests with #[cfg(test)] instead of the attribute value
3. Remember macro attributes are static: build a generated invocation from build.rs if config must vary

Example fix

// before
#[tauri::generate_context(test = "true")]
// after
#[tauri::generate_context(test = true)]

When it happens

Trigger: #[tauri::generate_context(test = "true")], test = 1, or test = cfg!(test) / is_ci() — every non-literal-bool expression trips the else branch.

Common situations: Quoting true out of JSON habit; trying to enable test mode conditionally per cfg profile; assuming runtime/compile-time expressions are allowed in attribute values.

Related errors

• unexpected expression for capability
• unexpected value for capabilities
• unknown attribute {name}
• unexpected list input
• unexpected list input

AI-assisted analysis of tauri-apps/tauri@52e4b6e71d (2026-08-20). Data as JSON: /api/errors/0880ffd662fd7f34. Report an issue: GitHub.