Refine testify assertions in tests for clearer failures and lint-aligned patterns (#4051)

This PR addresses the Go Fan/testify review by replacing low-signal
assertion patterns with more specific testify assertions across the
reported test areas. The goal is to improve failure diagnostics and
align tests with current assertion best practices without changing
production behavior.

- **Assertion specificity cleanup**
  - Replaced boolean equality assertions with direct boolean assertions:
- `assert.Equal(t, true/false, ...)` → `assert.True(...)` /
`assert.False(...)`
  - Replaced generic substring checks:
    - `assert.True(t, strings.Contains(...))` → `assert.Contains(...)`
- `assert.False(t, strings.Contains(...))` → `assert.NotContains(...)`
  - Replaced length-comparison boolean assertions:
    - `assert.True(t, len(x) <= N)` → `assert.LessOrEqual(t, len(x), N)`
- Replaced one compound substring OR check with `assert.Regexp(...)` for
direct intent.

- **Typed-nil error assertion handling in `rules_test.go`**
- The five `require.Nil(t, err)` sites were updated to
`require.NoError(...)` semantics while preserving behavior for typed-nil
`*ValidationError` returns.
  - Added a tiny adapter helper used only in tests:
    - `validationErrAsError(err *ValidationError) error`

- **Test import cleanup**
- Removed now-unused `strings` imports in files where
`assert.Contains`/`assert.NotContains` replaced manual
`strings.Contains` calls.

```go
// Before
assert.True(t, strings.Contains(text, "Bug report"), "response text should contain the issue title")

// After
assert.Contains(t, text, "Bug report", "response text should contain the issue title")
```

> [!WARNING]
>
> <details>
> <summary>Firewall rules blocked me from connecting to one or more
addresses (expand for details)</summary>
>
> #### I tried to connect to the following addresses, but was blocked by
firewall rules:
>
> - `example.com`
> - Triggering command: `/tmp/go-build850057972/b514/launcher.test
/tmp/go-build850057972/b514/launcher.test
-test.testlogfile=/tmp/go-build850057972/b514/testlog.txt
-test.paniconexit0 -test.timeout=10m0s E=3 .cfg /tmp/go-build403-w
x_amd64/vet . --gdwarf2 --64 x_amd64/vet -I .cfg
TiyY/dyEj6sNqXXBEEx-BTiyY x_amd64/vet --gdwarf-5 g/grpc/internal/-qE -o
x_amd64/vet` (dns block)
> - `invalid-host-that-does-not-exist-12345.com`
> - Triggering command: `/tmp/go-build850057972/b496/config.test
/tmp/go-build850057972/b496/config.test
-test.testlogfile=/tmp/go-build850057972/b496/testlog.txt
-test.paniconexit0 -test.timeout=10m0s
/tmp/go-build850057972/b394/vet.cfg @v1.1.3/cpu/x86/-errorsas -I
x_amd64/vet --gdwarf-5 .io/otel/baggage-atomic -o x_amd64/vet 2483��
g_.a L_XeGB1fo x_amd64/vet -p vendor/golang.or-atomic -lang=go1.25
x_amd64/vet` (dns block)
> - Triggering command: `/tmp/go-build772277680/b224/config.test
/tmp/go-build772277680/b224/config.test
-test.testlogfile=/tmp/go-build772277680/b224/testlog.txt
-test.paniconexit0 -test.timeout=10m0s rtcf�� by/280457505e8d1REDACTED y
ache/go/1.25.8/x64/pkg/tool/linujson
ntime.v2.task/mo/usr/libexec/docker/cli-plugins/docker-buildx
-ifaceassert -nilfunc ache/go/1.25.8/x64/pkg/tool/linu--no-legend
&#34;SSL�� ef5286be851aaba1bad991c168a5fac9-- -tests
ker/cli-plugins/docker-compose by/c68777e185eb8node
ache/go/1.25.8/xmock-mcp-server.js x_amd64/vet fce/log.json` (dns block)
> - `nonexistent.local`
> - Triggering command: `/tmp/go-build850057972/b514/launcher.test
/tmp/go-build850057972/b514/launcher.test
-test.testlogfile=/tmp/go-build850057972/b514/testlog.txt
-test.paniconexit0 -test.timeout=10m0s E=3 .cfg /tmp/go-build403-w
x_amd64/vet . --gdwarf2 --64 x_amd64/vet -I .cfg
TiyY/dyEj6sNqXXBEEx-BTiyY x_amd64/vet --gdwarf-5 g/grpc/internal/-qE -o
x_amd64/vet` (dns block)
> - `slow.example.com`
> - Triggering command: `/tmp/go-build850057972/b514/launcher.test
/tmp/go-build850057972/b514/launcher.test
-test.testlogfile=/tmp/go-build850057972/b514/testlog.txt
-test.paniconexit0 -test.timeout=10m0s E=3 .cfg /tmp/go-build403-w
x_amd64/vet . --gdwarf2 --64 x_amd64/vet -I .cfg
TiyY/dyEj6sNqXXBEEx-BTiyY x_amd64/vet --gdwarf-5 g/grpc/internal/-qE -o
x_amd64/vet` (dns block)
> - `this-host-does-not-exist-12345.com`
> - Triggering command: `/tmp/go-build850057972/b523/mcp.test
/tmp/go-build850057972/b523/mcp.test
-test.testlogfile=/tmp/go-build850057972/b523/testlog.txt
-test.paniconexit0 -test.timeout=10m0s .cfg�� 2483721/b343/_pkg_.a -fPIC
x_amd64/vet us.pb.go g/grpc/balancer -fmessage-length=0 x_amd64/vet
.cfg�� /oidc/errors.go /oidc/provider.go x_amd64/vet -dynout
g/grpc/health/gr/usr/bin/runc -ffile-prefix-ma--version x_amd64/vet`
(dns block)
> - Triggering command: `/tmp/go-build772277680/b484/mcp.test
/tmp/go-build772277680/b484/mcp.test
-test.testlogfile=/tmp/go-build772277680/b484/testlog.txt
-test.paniconexit0 -test.timeout=10m0s -ato�� -bool y
etc/ssl/certs/ca-certificates.crt&#34;,
&#34;REQUESTS_CA_BUNDLE=/etc/ssl/certs/ca-certifi 3cfebab8779a2365/check
-ifaceassert -nilfunc noffline 287f��
ef5286be851aaba1bad991c168a5fac9/run/containerd/io.containerd.runtime.v2.task/moby/5878ee59bbb48go
3cfebab8779a2365c0a0927369ddf64be3c02162ae57d53bf27 /usr/bin/grep
9381bd4d1eab940e/usr/bin/runc.original` (dns block)
>
> If you need me to access, download, or install something from one of
these locations, you can either:
>
> - Configure [Actions setup
steps](https://gh.io/copilot/actions-setup-steps) to set up my
environment, which run before the firewall is enabled
> - Add the appropriate URLs or hosts to the custom allowlist in this
repository's [Copilot coding agent
settings](https://github.com/github/gh-aw-mcpg/settings/copilot/coding_agent)
(admins only)
>
> </details>

Author: lpcox

internal/config/config_test.go

@@ -1089,7 +1089,7 @@ port 3000
 	errMsg := err.Error()
 	assert.Contains(t, errMsg, "line", "Error should mention line number")
 	// Our improved format includes "column" explicitly when ParseError is detected
-	assert.True(t, strings.Contains(errMsg, "column") || strings.Contains(errMsg, "line 2"),
+	assert.Regexp(t, `\bcolumn\b|\bline\s+2\b`, errMsg,
 		"Error should mention column or line position, got: %s", errMsg)
 }
 

internal/config/expand_raw_json_test.go

@@ -1,7 +1,6 @@
 package config
 
 import (
-	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -566,7 +565,7 @@ func TestValidateMounts(t *testing.T) {
 			if tt.shouldErr {
 				require.Error(t, err, "Expected an error but got none")
 				if tt.errMsg != "" {
-					assert.True(t, strings.Contains(err.Error(), tt.errMsg),
+					assert.Contains(t, err.Error(), tt.errMsg,
 						"Error message %q should contain %q", err.Error(), tt.errMsg)
 				}
 			} else {

internal/config/fetch_and_fix_schema_test.go

@@ -245,7 +245,10 @@ func TestFixSchemaBytes_AddRegistryAndGuardPoliciesToStdioConfig(t *testing.T) {
 	require.True(t, hasGuardPolicies, "guard-policies field should be added to stdioServerConfig.properties")
 	gpMap := guardPolicies.(map[string]interface{})
 	assert.Equal(t, "object", gpMap["type"], "guard-policies.type should be 'object'")
-	assert.Equal(t, true, gpMap["additionalProperties"], "guard-policies.additionalProperties should be true")
+	additionalProperties, hasAdditionalProperties := gpMap["additionalProperties"]
+	require.True(t, hasAdditionalProperties, "guard-policies.additionalProperties should be present")
+	require.IsType(t, true, additionalProperties, "guard-policies.additionalProperties should be a bool")
+	assert.True(t, additionalProperties.(bool), "guard-policies.additionalProperties should be true")
 }
 
 // TestFixSchemaBytes_AddRegistryAndGuardPoliciesToHttpConfig covers the injection

internal/config/rules/rules_test.go

@@ -9,6 +9,13 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func validationErrAsError(err *ValidationError) error {
+	if err == nil {
+		return nil
+	}
+	return err
+}
+
 func TestPortRange(t *testing.T) {
 	tests := []struct {
 		name      string
@@ -74,7 +81,7 @@ func TestPortRange(t *testing.T) {
 				assert.Contains(t, err.Message, tt.errMsg, "Error message should contain expected text")
 				assert.Equal(t, tt.jsonPath, err.JSONPath, "JSONPath should match")
 			} else {
-				require.Nil(t, err, "Unexpected validation error")
+				require.NoError(t, validationErrAsError(err), "Unexpected validation error")
 			}
 		})
 	}
@@ -138,7 +145,7 @@ func TestTimeoutPositive(t *testing.T) {
 				assert.Equal(t, tt.jsonPath, err.JSONPath, "JSONPath should match")
 				assert.Equal(t, tt.fieldName, err.Field, "Field name should match")
 			} else {
-				require.Nil(t, err, "Unexpected validation error")
+				require.NoError(t, validationErrAsError(err), "Unexpected validation error")
 			}
 		})
 	}
@@ -295,7 +302,7 @@ func TestMountFormat(t *testing.T) {
 				assert.Contains(t, err.Message, tt.errMsg, "Error message should contain expected text")
 				assert.Equal(t, fmt.Sprintf("%s.mounts[%d]", tt.jsonPath, tt.index), err.JSONPath, "JSONPath should match expected pattern")
 			} else {
-				require.Nil(t, err, "Unexpected validation error")
+				require.NoError(t, validationErrAsError(err), "Unexpected validation error")
 			}
 		})
 	}
@@ -899,7 +906,7 @@ func TestNonEmptyString(t *testing.T) {
 				assert.Contains(t, err.Error(), tt.errMsg)
 				assert.Contains(t, err.Error(), tt.jsonPath)
 			} else {
-				require.Nil(t, err, "Unexpected validation error")
+				require.NoError(t, validationErrAsError(err), "Unexpected validation error")
 			}
 		})
 	}
@@ -1039,7 +1046,7 @@ func TestAbsolutePath(t *testing.T) {
 				assert.Contains(t, err.Error(), tt.errMsg)
 				assert.Contains(t, err.Error(), tt.jsonPath)
 			} else {
-				require.Nil(t, err, "Unexpected validation error")
+				require.NoError(t, validationErrAsError(err), "Unexpected validation error")
 			}
 		})
 	}

internal/difc/labels_test.go

@@ -1,7 +1,6 @@
 package difc
 
 import (
-	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -590,11 +589,11 @@ func TestViolationError_Error(t *testing.T) {
 			msg := tt.err.Error()
 			assert.NotEmpty(t, msg)
 			for _, want := range tt.wantContains {
-				assert.True(t, strings.Contains(msg, want),
+				assert.Contains(t, msg, want,
 					"expected %q in error message %q", want, msg)
 			}
 			for _, absent := range tt.wantAbsent {
-				assert.False(t, strings.Contains(msg, absent),
+				assert.NotContains(t, msg, absent,
 					"expected %q NOT to be in error message %q", absent, msg)
 			}
 		})
@@ -616,7 +615,7 @@ func TestViolationError_Detailed(t *testing.T) {
 		base := err.Error()
 
 		// Detailed should contain the base error message
-		assert.True(t, strings.Contains(detailed, base), "detailed should include base error")
+		assert.Contains(t, detailed, base, "detailed should include base error")
 
 		// Detailed should include agent and resource tag context
 		assert.Contains(t, detailed, "Agent")

internal/mcp/tool_result_test.go

@@ -268,7 +268,9 @@ func TestParseToolArguments(t *testing.T) {
 		require.NotNil(t, args)
 		assert.Equal(t, "search term", args["query"])
 		assert.Equal(t, float64(10), args["limit"])
-		assert.Equal(t, true, args["active"])
+		active, ok := args["active"].(bool)
+		require.True(t, ok, "expected active to be a bool")
+		assert.True(t, active)
 	})
 
 	t.Run("nested object arguments are parsed correctly", func(t *testing.T) {

internal/mcp/unmarshal_params_test.go

@@ -153,7 +153,9 @@ func TestUnmarshalParams(t *testing.T) {
 		// JSON unmarshal converts numbers to float64 by default
 		assert.Equal(t, float64(42), target["int_val"])
 		assert.Equal(t, 3.14, target["float_val"])
-		assert.Equal(t, true, target["bool_val"])
+		boolVal, ok := target["bool_val"].(bool)
+		require.True(t, ok, "bool_val should be a bool")
+		assert.True(t, boolVal)
 		assert.Len(t, target["array_val"], 3)
 		assert.NotNil(t, target["object_val"])
 		assert.Nil(t, target["null_val"])

internal/middleware/jqschema_integration_test.go

@@ -195,7 +195,7 @@ func TestMiddlewareWithLargePayload(t *testing.T) {
 	// Verify preview truncation in Content field (preview ends with ... when truncated)
 	previewInContent := contentMap["payloadPreview"].(string)
 	if strings.HasSuffix(previewInContent, "...") {
-		assert.True(t, len(previewInContent) <= 503, "Preview in Content should be truncated")
+		assert.LessOrEqual(t, len(previewInContent), 503, "Preview in Content should be truncated")
 	}
 
 	// Also check data return value
@@ -204,7 +204,7 @@ func TestMiddlewareWithLargePayload(t *testing.T) {
 	// Verify preview truncation (check if it ends with ...)
 	preview := dataMap["payloadPreview"].(string)
 	if strings.HasSuffix(preview, "...") {
-		assert.True(t, len(preview) <= 503, "Preview should be truncated")
+		assert.LessOrEqual(t, len(preview), 503, "Preview should be truncated")
 	}
 
 	// Verify payload file has complete data

internal/proxy/proxy_test.go

@@ -682,7 +682,11 @@ func TestRewrapSearchResponse(t *testing.T) {
 		result := rewrapSearchResponse(original, filtered)
 		m := result.(map[string]interface{})
 		assert.Equal(t, float64(2), m["total_count"])
-		assert.Equal(t, false, m["incomplete_results"])
+		incompleteResults, ok := m["incomplete_results"]
+		require.True(t, ok)
+		incompleteResultsBool, ok := incompleteResults.(bool)
+		require.True(t, ok)
+		assert.False(t, incompleteResultsBool)
 		assert.Len(t, m["items"].([]interface{}), 2)
 	})
 

internal/proxy/rest_backend_caller_tool_test.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"net/http"
 	"net/http/httptest"
-	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -574,5 +573,5 @@ func TestRestBackendCaller_IssueRead_ResponseFormat(t *testing.T) {
 
 	text, ok := content[0]["text"].(string)
 	require.True(t, ok)
-	assert.True(t, strings.Contains(text, "Bug report"), "response text should contain the issue title")
+	assert.Contains(t, text, "Bug report", "response text should contain the issue title")
 }