test: increase test coverage for iostreams (#394)

* test: increase test coverage for iostreams

* test: rename test functions to use Test_FunctionName convention

Rename 12 test functions to follow the Test_StructName_FunctionName
and Test_FunctionName naming convention. Document the convention in
MAINTAINERS_GUIDE.md and CLAUDE.md.

* test: order test functions alphabetically and document convention

Reorder test functions added on this branch alphabetically within
their files, grouping getter/setter tests under the base name.
Document the test ordering convention in MAINTAINERS_GUIDE.md and
CLAUDE.md.

* docs: fix whitespace alignment in CLAUDE.md test naming example

* test: apply Test_StructName_FunctionName format and reorder alphabetically

* test: reorder format_test.go alphabetically and adjust test names

* docs: add constructor-first rule to test ordering conventions

Update CLAUDE.md and MAINTAINERS_GUIDE.md to state that constructor
functions (NewXYZ) should always be declared first at the top of test
files, before alphabetically ordered test functions. Also allow
exceptions when alphabetical ordering doesn't work well. Apply the
new rule to iostreams_test.go by moving Test_IOSteams_NewIOStreams
to the top of the file.

* test: revert survey_test.go to main for PR#404 compatibility

Remove tests added in this branch since PR#404 refactors this code
and includes similar test coverage.

Author: mwbrooks

.claude/CLAUDE.md

@@ -135,6 +135,19 @@ func NewExampleCommand(clients *shared.ClientFactory) *cobra.Command {
 - Mock the `ClientFactory` and its dependencies for testing
 - Always mock file system operations using `afero.Fs` to enable testability
 
+### Test Naming Conventions
+
+Test function names use the format `Test_StructName_FunctionName` for methods on a struct, or `Test_FunctionName` for package-level functions:
+
+```go
+func Test_Client_GetAppStatus(t *testing.T) { ... }  // struct method
+func Test_getKeyLength(t *testing.T) { ... }         // package-level function
+```
+
+### Test Ordering Conventions
+
+Constructor functions (`NewXYZ`) should always be declared first, at the top of the test file. After constructors, test functions should be ordered alphabetically within each file. When a file has logical sections (separated by comments), tests should be alphabetical within each section. Getter and setter functions are grouped together under the base name — ignore the `Get` or `Set` prefix when determining order (e.g. `Test_AppName` and `Test_SetAppName` both sort under `A`). Exceptions to alphabetical ordering can be made when it doesn't work well for readability or logical grouping.
+
 ### Table-Driven Test Conventions
 
 **Preferred: Map pattern** - uses `tc` for test case variable:

.github/MAINTAINERS_GUIDE.md

@@ -383,6 +383,34 @@ The branch name can also be set by changing
 for the `build-lint-test-e2e-test` workflow in the `.circleci/config.yml` file,
 but take care not to merge this change into `main`!
 
+#### Test naming conventions
+
+Test function names should use the format `Test_StructName_FunctionName` for methods
+on a struct, or `Test_FunctionName` for package-level functions. The underscore after
+`Test` separates the Go test prefix from the identifier being tested:
+
+```go
+// Testing a method on a struct
+func Test_Client_GetAppStatus(t *testing.T) { ... }
+
+// Testing a package-level function
+func Test_getKeyLength(t *testing.T) { ... }
+```
+
+#### Test ordering conventions
+
+Constructor functions (`NewXYZ`) should always be declared first, at the top of the
+test file. After constructors, test functions should be ordered alphabetically. When
+a file has logical sections (separated by comments), tests should be alphabetical
+within each section.
+
+Getter and setter functions should be grouped together under the base name. Ignore
+the `Get` or `Set` prefix when determining alphabetical order. For example,
+`Test_AppName` and `Test_SetAppName` are both sorted under `A` for `AppName`.
+
+Exceptions to alphabetical ordering can be made when it doesn't work well for
+readability or logical grouping.
+
 #### Contributing tests
 
 If you'd like to add tests, please review our

internal/iostreams/iostreams_test.go

@@ -20,6 +20,7 @@ import (
 
 	"github.com/slackapi/slack-cli/internal/config"
 	"github.com/slackapi/slack-cli/internal/slackdeps"
+	"github.com/spf13/cobra"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -34,6 +35,36 @@ func Test_IOSteams_NewIOStreams(t *testing.T) {
 	require.True(t, io.config.DebugEnabled, "iostreams references config")
 }
 
+func Test_IOStreams_ExitCode(t *testing.T) {
+	tests := map[string]struct {
+		setCode  ExitCode
+		expected ExitCode
+	}{
+		"default is ExitOK": {
+			setCode:  ExitOK,
+			expected: ExitOK,
+		},
+		"set to ExitError": {
+			setCode:  ExitError,
+			expected: ExitError,
+		},
+		"set to ExitCancel": {
+			setCode:  ExitCancel,
+			expected: ExitCancel,
+		},
+	}
+	for name, tc := range tests {
+		t.Run(name, func(t *testing.T) {
+			fsMock := slackdeps.NewFsMock()
+			osMock := slackdeps.NewOsMock()
+			cfg := config.NewConfig(fsMock, osMock)
+			io := NewIOStreams(cfg, fsMock, osMock)
+			io.SetExitCode(tc.setCode)
+			assert.Equal(t, tc.expected, io.GetExitCode())
+		})
+	}
+}
+
 func Test_IOStreams_IsTTY(t *testing.T) {
 	tests := map[string]struct {
 		fileInfo os.FileInfo
@@ -65,3 +96,15 @@ func Test_IOStreams_IsTTY(t *testing.T) {
 		})
 	}
 }
+
+func Test_IOStreams_SetCmdIO(t *testing.T) {
+	fsMock := slackdeps.NewFsMock()
+	osMock := slackdeps.NewOsMock()
+	cfg := config.NewConfig(fsMock, osMock)
+	io := NewIOStreams(cfg, fsMock, osMock)
+	cmd := &cobra.Command{Use: "test"}
+	io.SetCmdIO(cmd)
+	assert.NotNil(t, cmd.InOrStdin())
+	assert.NotNil(t, cmd.OutOrStdout())
+	assert.NotNil(t, cmd.ErrOrStderr())
+}

internal/iostreams/writer_test.go

@@ -199,6 +199,24 @@ func Test_FilteredWriter(t *testing.T) {
 	}
 }
 
+func Test_IOStreams_WriteErr(t *testing.T) {
+	fsMock := slackdeps.NewFsMock()
+	osMock := slackdeps.NewOsMock()
+	cfg := config.NewConfig(fsMock, osMock)
+	io := NewIOStreams(cfg, fsMock, osMock)
+	w := io.WriteErr()
+	require.NotNil(t, w)
+}
+
+func Test_IOStreams_WriteOut(t *testing.T) {
+	fsMock := slackdeps.NewFsMock()
+	osMock := slackdeps.NewOsMock()
+	cfg := config.NewConfig(fsMock, osMock)
+	io := NewIOStreams(cfg, fsMock, osMock)
+	w := io.WriteOut()
+	require.NotNil(t, w)
+}
+
 func Test_WriteIndent(t *testing.T) {
 	tests := map[string]struct {
 		input    string