Finding Existing Tests

Applies to: C# code only. If the production code in question is not C# - do not use this skill. Skip it silently and use the host's normal test-discovery approach. The underlying coverage tool only understands C# symbols.

Always use the findTests tool via execute_tool to locate existing tests for a given C# class and method. This tool queries the IDE code coverage data directly and is:

• Precise — returns exact test locations without false positives
• Token-efficient — no need for glob, grep, or directory listing guesses
• Fast — a single call replaces multiple rounds of searching

findTests

Find existing tests for a given production class and method. Supply the production code's class name, namespace, and file path — the tool returns the path of the single test file most relevant to the given method.

Syntax

execute_tool(command="findTests --className <value> --classNamespace <value> --filePath <value> [--methodName <value>] [--methodArguments <value>]")

Parameters

String parameters: Quote values containing spaces: --filePath '/Users/dev/MyProject/src/Services/OrderService.cs'

Examples

1. Class only — no method name

User says: "Find the tests for the JsonSerializer class"

{"tool":"execute_tool","arguments":{"command":"findTests --className JsonSerializer --classNamespace Newtonsoft.Json --filePath /projects/Newtonsoft.Json/Src/Newtonsoft.Json/JsonSerializer.cs"}}

2. With method name

User says: "Find tests for the Deserialize method in JsonSerializer"

{"tool":"execute_tool","arguments":{"command":"findTests --className JsonSerializer --classNamespace Newtonsoft.Json --filePath /projects/Newtonsoft.Json/Src/Newtonsoft.Json/JsonSerializer.cs --methodName Deserialize"}}

3. With method name and arg names — specific overload

User says: "Find tests for the Deserialize(TextReader reader, Type objectType) overload in JsonSerializer"

{"tool":"execute_tool","arguments":{"command":"findTests --className JsonSerializer --classNamespace Newtonsoft.Json --filePath /projects/Newtonsoft.Json/Src/Newtonsoft.Json/JsonSerializer.cs --methodName Deserialize --methodArguments 'TextReader reader, Type objectType'"}}

4. Generic class and method

User says: "Find tests for the ReadJson<TResult> method in JsonConverter<T>"

{"tool":"execute_tool","arguments":{"command":"findTests --className 'JsonConverter<T>' --classNamespace Newtonsoft.Json --filePath /projects/Newtonsoft.Json/Src/Newtonsoft.Json/JsonConverter.cs --methodName 'ReadJson<TResult>'"}}

5. Paths with spaces

{"tool":"execute_tool","arguments":{"command":"findTests --className DnsClient --classNamespace My.Network.Clients --filePath '/Users/dev/MyProject/src/Network Clients/DnsClient.cs' --methodName ResolveAsync"}}

Pitfalls

• Every --param MUST be followed by a value (no bare flags)
• Values with spaces must be quoted: --filePath '/Users/dev/MyProject/my folder/file.cs'
• Omit optional parameters entirely rather than passing empty strings
• All file paths must be absolute

Rules

1. C# only. Before invoking findTests, verify the production file is .cs. If it is any other language, do not invoke this skill or its tool — skip silently and fall back to standard test discovery.
2. Prefer findTests over glob, grep, or directory listing to find tests in C# code. These are wasteful and imprecise. If execute_tool is unavailable, fall back to grep/glob as a last resort and inform the user.
3. If findTests reports no tests exist, trust that result — do not retry with alternative search tools.
4. After finding tests, read them to understand the project's testing conventions before making any changes.

Troubleshooting

execute_tool not available

If execute_tool is not available, inform the user and fall back to grep/glob only as a last resort.

findTests via execute_tool timeout

If calling findTests via execute_tool times out, inform the user and fall back to your standard test discovery method. You may stop trying findTests if it timeouts for three times in a row.

No tests found

If findTests returns empty results, trust the result. Do not retry with alternative search methods.