[Efficiency Improver] perf: reduce allocations in BFSTestNodeVisitor path tracking and WrappedName building by Evangelink · Pull Request #7836 · microsoft/testfx

Amaury Levé (Evangelink) · 2026-04-25T20:17:01Z

Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path.
Replace HashSet with HashSet for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet.
Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry.

Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid
per node (filter lookup).
After: 1 string per node (path), no PlatformTestNodeUid per lookup.

Fixes#7828

…teWrappedName - Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path. - Replace HashSet<PlatformTestNodeUid> with HashSet<string> for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet. - Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry. Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid per node (filter lookup). After: 1 string per node (path), no PlatformTestNodeUid per lookup. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

This PR reduces heap allocations in MSTest.Engine’s test-node discovery/execution pipeline by simplifying per-node path tracking in BFSTestNodeVisitor and by removing StringBuilder usage in argument display-name wrapping.

Changes:

Replace per-node StringBuilder path propagation in BFSTestNodeVisitor with immutable string path tracking.
Avoid per-lookup PlatformTestNodeUid wrapper allocations by switching UID filter membership checks to HashSet<string>.
Simplify TestArgumentsManager.CreateWrappedName to use string.Concat instead of StringBuilder.

Show a summary per file

File	Description
src/Adapter/MSTest.Engine/Engine/BFSTestNodeVisitor.cs	Removes per-node `StringBuilder` allocations in BFS traversal and reduces UID-filter lookup allocations by using string values directly.
src/Adapter/MSTest.Engine/Engine/TestArgumentsManager.cs	Removes `StringBuilder` allocation from wrapped-name formatting for argument fragments.

Copilot's findings

Files reviewed: 2/2 changed files
Comments generated: 2

…deVisitor Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/c99d957f-6c20-4942-988b-5c1977ecef1d Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

…nd cache PathSeparator as string field Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/eb488e40-99da-4224-81ee-95f9c0e4dc4b Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

Jan Krivanek (JanKrivanek) · 2026-04-27T07:20:13Z

Btw. PR description got likely half eaten out

Amaury Levé (Evangelink) · 2026-04-25T20:17:01Z

Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path.
Replace HashSet with HashSet for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet.
Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry.

Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid
per node (filter lookup).
After: 1 string per node (path), no PlatformTestNodeUid per lookup.

Fixes#7828

…teWrappedName - Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path. - Replace HashSet<PlatformTestNodeUid> with HashSet<string> for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet. - Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry. Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid per node (filter lookup). After: 1 string per node (path), no PlatformTestNodeUid per lookup. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

This PR reduces heap allocations in MSTest.Engine’s test-node discovery/execution pipeline by simplifying per-node path tracking in BFSTestNodeVisitor and by removing StringBuilder usage in argument display-name wrapping.

Changes:

Replace per-node StringBuilder path propagation in BFSTestNodeVisitor with immutable string path tracking.
Avoid per-lookup PlatformTestNodeUid wrapper allocations by switching UID filter membership checks to HashSet<string>.
Simplify TestArgumentsManager.CreateWrappedName to use string.Concat instead of StringBuilder.

Show a summary per file

File	Description
src/Adapter/MSTest.Engine/Engine/BFSTestNodeVisitor.cs	Removes per-node `StringBuilder` allocations in BFS traversal and reduces UID-filter lookup allocations by using string values directly.
src/Adapter/MSTest.Engine/Engine/TestArgumentsManager.cs	Removes `StringBuilder` allocation from wrapped-name formatting for argument fragments.

Copilot's findings

Files reviewed: 2/2 changed files
Comments generated: 2

…deVisitor Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/c99d957f-6c20-4942-988b-5c1977ecef1d Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

…nd cache PathSeparator as string field Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/eb488e40-99da-4224-81ee-95f9c0e4dc4b Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

Jan Krivanek (JanKrivanek) · 2026-04-27T07:20:13Z

Btw. PR description got likely half eaten out

Amaury Levé (Evangelink) · 2026-04-25T20:17:01Z

Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path.
Replace HashSet with HashSet for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet.
Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry.

Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid
per node (filter lookup).
After: 1 string per node (path), no PlatformTestNodeUid per lookup.

Fixes#7828

…teWrappedName - Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path. - Replace HashSet<PlatformTestNodeUid> with HashSet<string> for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet. - Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry. Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid per node (filter lookup). After: 1 string per node (path), no PlatformTestNodeUid per lookup. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

This PR reduces heap allocations in MSTest.Engine’s test-node discovery/execution pipeline by simplifying per-node path tracking in BFSTestNodeVisitor and by removing StringBuilder usage in argument display-name wrapping.

Changes:

Replace per-node StringBuilder path propagation in BFSTestNodeVisitor with immutable string path tracking.
Avoid per-lookup PlatformTestNodeUid wrapper allocations by switching UID filter membership checks to HashSet<string>.
Simplify TestArgumentsManager.CreateWrappedName to use string.Concat instead of StringBuilder.

Show a summary per file

File	Description
src/Adapter/MSTest.Engine/Engine/BFSTestNodeVisitor.cs	Removes per-node `StringBuilder` allocations in BFS traversal and reduces UID-filter lookup allocations by using string values directly.
src/Adapter/MSTest.Engine/Engine/TestArgumentsManager.cs	Removes `StringBuilder` allocation from wrapped-name formatting for argument fragments.

Copilot's findings

Files reviewed: 2/2 changed files
Comments generated: 2

…deVisitor Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/c99d957f-6c20-4942-988b-5c1977ecef1d Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

…nd cache PathSeparator as string field Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/eb488e40-99da-4224-81ee-95f9c0e4dc4b Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

Jan Krivanek (JanKrivanek) · 2026-04-27T07:20:13Z

Btw. PR description got likely half eaten out

Amaury Levé (Evangelink) · 2026-04-25T20:17:01Z

Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path.
Replace HashSet with HashSet for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet.
Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry.

Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid
per node (filter lookup).
After: 1 string per node (path), no PlatformTestNodeUid per lookup.

Fixes#7828

…teWrappedName - Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path. - Replace HashSet<PlatformTestNodeUid> with HashSet<string> for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet. - Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry. Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid per node (filter lookup). After: 1 string per node (path), no PlatformTestNodeUid per lookup. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

This PR reduces heap allocations in MSTest.Engine’s test-node discovery/execution pipeline by simplifying per-node path tracking in BFSTestNodeVisitor and by removing StringBuilder usage in argument display-name wrapping.

Changes:

Replace per-node StringBuilder path propagation in BFSTestNodeVisitor with immutable string path tracking.
Avoid per-lookup PlatformTestNodeUid wrapper allocations by switching UID filter membership checks to HashSet<string>.
Simplify TestArgumentsManager.CreateWrappedName to use string.Concat instead of StringBuilder.

Show a summary per file

File	Description
src/Adapter/MSTest.Engine/Engine/BFSTestNodeVisitor.cs	Removes per-node `StringBuilder` allocations in BFS traversal and reduces UID-filter lookup allocations by using string values directly.
src/Adapter/MSTest.Engine/Engine/TestArgumentsManager.cs	Removes `StringBuilder` allocation from wrapped-name formatting for argument fragments.

Copilot's findings

Files reviewed: 2/2 changed files
Comments generated: 2

…deVisitor Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/c99d957f-6c20-4942-988b-5c1977ecef1d Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

…nd cache PathSeparator as string field Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/eb488e40-99da-4224-81ee-95f9c0e4dc4b Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

Jan Krivanek (JanKrivanek) · 2026-04-27T07:20:13Z

Btw. PR description got likely half eaten out

Amaury Levé (Evangelink) · 2026-04-25T20:17:01Z

Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path.
Replace HashSet with HashSet for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet.
Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry.

Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid
per node (filter lookup).
After: 1 string per node (path), no PlatformTestNodeUid per lookup.

Fixes#7828

…teWrappedName - Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path. - Replace HashSet<PlatformTestNodeUid> with HashSet<string> for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet. - Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry. Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid per node (filter lookup). After: 1 string per node (path), no PlatformTestNodeUid per lookup. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

This PR reduces heap allocations in MSTest.Engine’s test-node discovery/execution pipeline by simplifying per-node path tracking in BFSTestNodeVisitor and by removing StringBuilder usage in argument display-name wrapping.

Changes:

Replace per-node StringBuilder path propagation in BFSTestNodeVisitor with immutable string path tracking.
Avoid per-lookup PlatformTestNodeUid wrapper allocations by switching UID filter membership checks to HashSet<string>.
Simplify TestArgumentsManager.CreateWrappedName to use string.Concat instead of StringBuilder.

Show a summary per file

File	Description
src/Adapter/MSTest.Engine/Engine/BFSTestNodeVisitor.cs	Removes per-node `StringBuilder` allocations in BFS traversal and reduces UID-filter lookup allocations by using string values directly.
src/Adapter/MSTest.Engine/Engine/TestArgumentsManager.cs	Removes `StringBuilder` allocation from wrapped-name formatting for argument fragments.

Copilot's findings

Files reviewed: 2/2 changed files
Comments generated: 2

…deVisitor Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/c99d957f-6c20-4942-988b-5c1977ecef1d Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

…nd cache PathSeparator as string field Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/eb488e40-99da-4224-81ee-95f9c0e4dc4b Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

Jan Krivanek (JanKrivanek) · 2026-04-27T07:20:13Z

Btw. PR description got likely half eaten out

Amaury Levé (Evangelink) · 2026-04-25T20:17:01Z

Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path.
Replace HashSet with HashSet for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet.
Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry.

Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid
per node (filter lookup).
After: 1 string per node (path), no PlatformTestNodeUid per lookup.

Fixes#7828

…teWrappedName - Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path. - Replace HashSet<PlatformTestNodeUid> with HashSet<string> for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet. - Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry. Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid per node (filter lookup). After: 1 string per node (path), no PlatformTestNodeUid per lookup. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

This PR reduces heap allocations in MSTest.Engine’s test-node discovery/execution pipeline by simplifying per-node path tracking in BFSTestNodeVisitor and by removing StringBuilder usage in argument display-name wrapping.

Changes:

Replace per-node StringBuilder path propagation in BFSTestNodeVisitor with immutable string path tracking.
Avoid per-lookup PlatformTestNodeUid wrapper allocations by switching UID filter membership checks to HashSet<string>.
Simplify TestArgumentsManager.CreateWrappedName to use string.Concat instead of StringBuilder.

Show a summary per file

File	Description
src/Adapter/MSTest.Engine/Engine/BFSTestNodeVisitor.cs	Removes per-node `StringBuilder` allocations in BFS traversal and reduces UID-filter lookup allocations by using string values directly.
src/Adapter/MSTest.Engine/Engine/TestArgumentsManager.cs	Removes `StringBuilder` allocation from wrapped-name formatting for argument fragments.

Copilot's findings

Files reviewed: 2/2 changed files
Comments generated: 2

…deVisitor Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/c99d957f-6c20-4942-988b-5c1977ecef1d Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

…nd cache PathSeparator as string field Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/eb488e40-99da-4224-81ee-95f9c0e4dc4b Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

Jan Krivanek (JanKrivanek) · 2026-04-27T07:20:13Z

Btw. PR description got likely half eaten out

Amaury Levé (Evangelink) · 2026-04-25T20:17:01Z

Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path.
Replace HashSet with HashSet for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet.
Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry.

Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid
per node (filter lookup).
After: 1 string per node (path), no PlatformTestNodeUid per lookup.

Fixes#7828

…teWrappedName - Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path. - Replace HashSet<PlatformTestNodeUid> with HashSet<string> for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet. - Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry. Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid per node (filter lookup). After: 1 string per node (path), no PlatformTestNodeUid per lookup. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

This PR reduces heap allocations in MSTest.Engine’s test-node discovery/execution pipeline by simplifying per-node path tracking in BFSTestNodeVisitor and by removing StringBuilder usage in argument display-name wrapping.

Changes:

Replace per-node StringBuilder path propagation in BFSTestNodeVisitor with immutable string path tracking.
Avoid per-lookup PlatformTestNodeUid wrapper allocations by switching UID filter membership checks to HashSet<string>.
Simplify TestArgumentsManager.CreateWrappedName to use string.Concat instead of StringBuilder.

Show a summary per file

File	Description
src/Adapter/MSTest.Engine/Engine/BFSTestNodeVisitor.cs	Removes per-node `StringBuilder` allocations in BFS traversal and reduces UID-filter lookup allocations by using string values directly.
src/Adapter/MSTest.Engine/Engine/TestArgumentsManager.cs	Removes `StringBuilder` allocation from wrapped-name formatting for argument fragments.

Copilot's findings

Files reviewed: 2/2 changed files
Comments generated: 2

…deVisitor Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/c99d957f-6c20-4942-988b-5c1977ecef1d Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

…nd cache PathSeparator as string field Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/eb488e40-99da-4224-81ee-95f9c0e4dc4b Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

Jan Krivanek (JanKrivanek) · 2026-04-27T07:20:13Z

Btw. PR description got likely half eaten out

Amaury Levé (Evangelink) · 2026-04-25T20:17:01Z

Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path.
Replace HashSet with HashSet for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet.
Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry.

Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid
per node (filter lookup).
After: 1 string per node (path), no PlatformTestNodeUid per lookup.

Fixes#7828

…teWrappedName - Replace StringBuilder in the BFS queue with string, eliminating one StringBuilder allocation per test node during tree traversal. Each node's full path is now an immutable string shared directly with child nodes as their base path. - Replace HashSet<PlatformTestNodeUid> with HashSet<string> for UID filter lookups. This avoids allocating a temporary PlatformTestNodeUid wrapper object on every node lookup in the HashSet. - Simplify CreateWrappedName in TestArgumentsManager to a conditional string.Concat, removing a StringBuilder allocation per argument entry. Proxy metric: heap allocations per test node during BFS traversal. Before: 1 StringBuilder + 1 string per node (path) + 1 PlatformTestNodeUid per node (filter lookup). After: 1 string per node (path), no PlatformTestNodeUid per lookup. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

This PR reduces heap allocations in MSTest.Engine’s test-node discovery/execution pipeline by simplifying per-node path tracking in BFSTestNodeVisitor and by removing StringBuilder usage in argument display-name wrapping.

Changes:

Replace per-node StringBuilder path propagation in BFSTestNodeVisitor with immutable string path tracking.
Avoid per-lookup PlatformTestNodeUid wrapper allocations by switching UID filter membership checks to HashSet<string>.
Simplify TestArgumentsManager.CreateWrappedName to use string.Concat instead of StringBuilder.

Show a summary per file

File	Description
src/Adapter/MSTest.Engine/Engine/BFSTestNodeVisitor.cs	Removes per-node `StringBuilder` allocations in BFS traversal and reduces UID-filter lookup allocations by using string values directly.
src/Adapter/MSTest.Engine/Engine/TestArgumentsManager.cs	Removes `StringBuilder` allocation from wrapped-name formatting for argument fragments.

Copilot's findings

Files reviewed: 2/2 changed files
Comments generated: 2

…deVisitor Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/c99d957f-6c20-4942-988b-5c1977ecef1d Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

…nd cache PathSeparator as string field Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/eb488e40-99da-4224-81ee-95f9c0e4dc4b Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

Jan Krivanek (JanKrivanek) · 2026-04-27T07:20:13Z

Btw. PR description got likely half eaten out

CopilotAI review requested due to automatic review settings April 25, 2026 20:17

Copilotstarted reviewing on behalf of Amaury Levé (Evangelink)April 25, 2026 20:17 View session

CopilotAI reviewed Apr 25, 2026
View reviewed changes

Comment threadsrc/Adapter/MSTest.Engine/Engine/BFSTestNodeVisitor.cs
Comment threadsrc/Adapter/MSTest.Engine/Engine/BFSTestNodeVisitor.cs Outdated

This was referenced Apr 26, 2026
[Efficiency Improver] Monthly Activity 2026-04 #7829
Closed
[Perf Improver] Monthly Activity 2026-04 #7816
Closed

Copilotstarted work on behalf of Amaury Levé (Evangelink)April 26, 2026 15:45 View session

Amaury Levé (Evangelink) enabled auto-merge (squash) April 26, 2026 15:45

Fix PathSeparator consistency and HashSet initialization in BFSTestNo…
9840f56
…deVisitor Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/c99d957f-6c20-4942-988b-5c1977ecef1d Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

Copilotfinished work on behalf of Amaury Levé (Evangelink)April 26, 2026 15:53

Fix BFSTestNodeVisitor: use StringComparer.Ordinal for uidFilterSet a…
4b5eb7d
…nd cache PathSeparator as string field Agent-Logs-Url: https://github.com/microsoft/testfx/sessions/eb488e40-99da-4224-81ee-95f9c0e4dc4b Co-authored-by: Evangelink <11340282+Evangelink@users.noreply.github.com>

CopilotAI review requested due to automatic review settings April 26, 2026 15:57

Amaury Levé (Evangelink) removed the request for review from Copilot April 26, 2026 15:57

Copilotfinished work on behalf of Amaury Levé (Evangelink)April 26, 2026 15:57

Jan Krivanek (JanKrivanek) approved these changes Apr 27, 2026
View reviewed changes

Amaury Levé (Evangelink) merged commit d7064a8 into mainApr 27, 2026
24 checks passed

Amaury Levé (Evangelink) deleted the efficiency/bfstestnode-string-path-tracking-f474c342a1a32973 branch April 27, 2026 07:25

This was referenced Apr 28, 2026
[Efficiency Improver] Monthly Activity 2026-04 #7884
Closed
[Efficiency Improver] Monthly Activity 2026-04 #7915
Closed

CopilotAI mentioned this pull request Apr 29, 2026
Eliminate delegate allocation in AbortForMaxFailedTestsExtension #7923
Merged

Amaury Levé (Evangelink) mentioned this pull request Apr 30, 2026
[Efficiency Improver] Monthly Activity 2026-04 #7948
Closed
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