feat: please introduce a better testing strategy

[tafelnl]

First of all, thanks for your work on this essential plugin for Vue.

I have an important 'feature' request, which I think is necessary to be able to release a stable version of this plugin. And it's about implementing a solid testing strategy.

Everytime a new release is published, a bunch of regression or new bugs show up. This is the ultimate sign of a bad testing strategy. And it's true, because most PRs (both features and bug fixes) get merged without an accompanying test.

A few examples of issues, that probably could have been prevented with proper testing:

• Cached result is not instantly returned when fetchPolicy is set to "cache-and-network" #1315
• vue/apollo-composable useQuery does not re-trigger from changes in variables ref, with Vue 2.7 #1397
• Hydration mismatch error because initial CSR render differs from SSR render #1432
• Latest version v4.0.0-beta.4 causes regression in CI with ES imports with @vue/apollo-composable #1462
• Typescript won't recognize fetchPolicy value as valid #936
• v3.0.0 regression: TypeScript mixins broken in v3.0.0, working fine in rc7 #847
• 4.0.0-alpha.16 breaks on ssr #1297
• vue-apollo-components are registered twice #1336

and probably some more.

A few examples of recently merged PRs without an accompanying test:

• fix(@vue/apollo-option): ssr cleanup function fails to run (#1424) #1425
• fix(composable): Remove immediate result logic #1388

[websitevirtuoso]

I think the owner of the lib will always get help, like new tests, bug fixes, improvements, and any related help.