fix: prefer AsSpan over Substring where span overloads are available

[vbreuss]

No description provided.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Test Results

    7 files  ±0      7 suites  ±0   7s ⏱️ -1s
  508 tests ±0    507 ✅ ±0  1 💤 ±0  0 ❌ ±0 
2 968 runs  ±0  2 967 ✅ ±0  1 💤 ±0  0 ❌ ±0 

Results for commit db19153. ± Comparison against base commit 97e4371.

[Copilot]

Pull request overview

This PR optimizes string slicing by using span-based APIs on newer TFMs (net8.0+ / net10.0) to avoid allocations, while keeping Substring for netstandard2.0 compatibility.

Changes:

• Use Guid.TryParse(ReadOnlySpan<char>) with value.AsSpan(...) for net8.0+ in ExpectationJsonConverter.
• Use StringBuilder.Append(ReadOnlySpan<char>) with line.AsSpan(...) for net8.0+ in TrimCommonWhiteSpace.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
Source/aweXpect.Json/Json/ExpectationJsonConverter.cs	Uses AsSpan for parsing the GUID suffix on net8.0+ to avoid substring allocation.
Source/aweXpect.Json/Helpers/StringExtensions.cs	Uses AsSpan when appending trimmed lines on net8.0+ to reduce allocations.

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[github-actions]

👽 Mutation Results

aweXpect.Json

Details

File	Score	Killed	Survived	Timeout	No Coverage	Ignored	Compile Errors	Total Detected	Total Undetected	Total Mutants
Helpers/StringExtensions.cs	75.00%	18	6	0	0	9	4	18	6	37
Json/ExpectationJsonConverter.cs	75.00%	6	0	0	2	5	6	6	2	19

The final mutation score is 75.00%

Coverage Thresholds: high:80 low:60 break:0

[github-actions]

🚀 Benchmark Results

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 24.04.4 LTS (Noble Numbat)

AMD EPYC 7763 2.63GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.203

[Host]     : .NET 8.0.26 (8.0.26, 8.0.2626.16921), X64 RyuJIT x86-64-v3

DefaultJob : .NET 8.0.26 (8.0.26, 8.0.2626.16921), X64 RyuJIT x86-64-v3

Method	Mean	Error	StdDev	Gen0	Gen1	Gen2	Allocated
IsValidJson_aweXpect	1.673 μs	0.0074 μs	0.0061 μs	0.0820	0.0038	0.0019	1.38 KB

[github-actions]

This is addressed in release v1.7.0.