Derive Macro TestVectorSet

#[derive(TestVectorSet)]
{
    // Attributes available to this derive:
    #[test_vec]
}

Derive macro for [assert_tv::TestVectorSet].

This macro generates an implementation of

impl assert_tv::TestVectorSet for YourStruct { … }

whose start::<TV>() constructor populates each field with an [assert_tv::TestValue<T>] pre‑initialised for the current source‑code location.

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Requirements

• All struct fields must be of type TestValue<…>.
• The struct must be non‑tuple, non‑unit, with named fields.

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Field attributes

Each field may carry zero or more #[test_vec(...)] helpers:

Key	Type	Meaning	Default if omitted
name	&'static str	Human‑readable display name.	None
description	&'static str	Longer explanation for docs / reports.	None
serialize_with	path to fn(&T) -> anyhow::Result<serde_json::Value>	Custom serializer	serde_json::to_value
deserialize_with	path to fn(&serde_json::Value) -> anyhow::Result<T>	Custom deserializer	serde_json::from_value

Multiple #[test_vec] attributes may be stacked on the same field:

#[test_vec(name = "counter")]
#[test_vec(description = "u64 monotonically increasing")]
#[test_vec(serialize_with = "my_serialize")]
count: TestValue<u64>,

Duplicate keys on the same field are rejected with a clear error (duplicate "name" key, etc.).

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Example

use assert_tv::{TestVectorSet, TestValue};

#[derive(TestVectorSet)]
struct SomeTestFields {
    #[test_vec(name = "a", description = "a is a u64")]
    #[test_vec(serialize_with = "custom_serialize_fn")]
    #[test_vec(deserialize_with = "custom_deserialize_fn")]
    a: TestValue<u64>,

    // No attributes: falls back to defaults.
    b: TestValue<String>,
}

fn custom_serialize_fn(v: &u64) -> anyhow::Result<serde_json::Value> {
    Ok(serde_json::json!(v))
}

fn custom_deserialize_fn(v: &serde_json::Value) -> anyhow::Result<u64> {
    Ok(v.as_u64().unwrap_or_default())
}

Running cargo doc --open after adding this comment will render the table, example, and key descriptions in a readable, searchable format.

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