test: refactor body cache tests

[mavonx]

What?

Refactors the test suite for email body cache.

Why?

The previous implementation only covered a few narrow scenarios and failed to test the system under most practical edge cases.

Closes #887

[floatpanebot]

Benchmark report — no significant change

Metrics worse: 0 · better: 0 (threshold: ±3%).

benchstat output

goos: linux
goarch: amd64
pkg: github.com/floatpane/matcha/backend
cpu: AMD EPYC 7763 64-Core Processor                
                           │    old.txt    │               new.txt                │
                           │    sec/op     │    sec/op      vs base               │
ParseSearchQuery_Simple-4    3.009µ ± 122%   2.630µ ± 322%        ~ (p=0.513 n=6)
ParseSearchQuery_Complex-4   7.778µ ±  33%   5.598µ ±  23%  -28.03% (p=0.026 n=6)
TokenizeSearchQuery-4        4.559µ ±  29%   3.534µ ±  60%        ~ (p=0.699 n=6)
geomean                      4.743µ          3.733µ         -21.29%

                           │  old.txt   │              new.txt               │
                           │    B/op    │    B/op     vs base                │
ParseSearchQuery_Simple-4    26.00 ± 0%   26.00 ± 0%       ~ (p=1.000 n=6) ¹
ParseSearchQuery_Complex-4   762.0 ± 0%   762.0 ± 0%       ~ (p=1.000 n=6) ¹
TokenizeSearchQuery-4        176.0 ± 0%   176.0 ± 0%       ~ (p=1.000 n=6) ¹
geomean                      151.6        151.6       +0.00%
¹ all samples are equal

                           │  old.txt   │              new.txt               │
                           │ allocs/op  │ allocs/op   vs base                │
ParseSearchQuery_Simple-4    2.000 ± 0%   2.000 ± 0%       ~ (p=1.000 n=6) ¹
ParseSearchQuery_Complex-4   23.00 ± 0%   23.00 ± 0%       ~ (p=1.000 n=6) ¹
TokenizeSearchQuery-4        9.000 ± 0%   9.000 ± 0%       ~ (p=1.000 n=6) ¹
geomean                      7.453        7.453       +0.00%
¹ all samples are equal

pkg: github.com/floatpane/matcha/tui
                    │   old.txt    │              new.txt               │
                    │    sec/op    │    sec/op     vs base              │
LogPanelView-4        170.7µ ± 16%   187.0µ ± 12%       ~ (p=0.093 n=6)
SearchOverlayView-4   187.2µ ±  9%   202.3µ ± 22%       ~ (p=0.310 n=6)
InboxConstruction-4   801.9µ ± 14%   854.5µ ±  8%  +6.56% (p=0.041 n=6)
geomean               294.8µ         318.6µ        +8.05%

                    │    old.txt    │                new.txt                │
                    │     B/op      │      B/op       vs base               │
LogPanelView-4        44.67Ki ± 51%   21.79Ki ± 105%        ~ (p=0.242 n=6)
SearchOverlayView-4   44.67Ki ± 26%   33.16Ki ±  69%        ~ (p=0.437 n=6)
InboxConstruction-4   874.0Ki ±  0%   873.9Ki ±   0%        ~ (p=0.734 n=6)
geomean               120.4Ki         85.79Ki         -28.73%

                    │   old.txt   │              new.txt              │
                    │  allocs/op  │  allocs/op   vs base              │
LogPanelView-4         714.0 ± 0%    712.5 ± 0%       ~ (p=0.242 n=6)
SearchOverlayView-4    925.0 ± 0%    923.0 ± 0%       ~ (p=0.567 n=6)
InboxConstruction-4   3.476k ± 0%   3.475k ± 0%       ~ (p=0.610 n=6)
geomean               1.319k        1.317k       -0.15%

_{auto-generated by benchmarks.yml}

[andrinoff]

@mavonx, please, drop 26c1f9a and c41b451 (git rebase -i HEAD~3 and place d (drop) instead of pick on these commits) don't forget to pull the branch

[mavonx]

@andrinoff

I’m going to do a small refactor and add a few more tests as well, so I’d prefer to hold the review for now.

I’ll mention you once it’s ready for review.

[andrinoff]

converting to draft will hold off reviews