test: improve code coverage with comprehensive unit tests

Author: dlevy-msft-sql

.github/copilot-instructions.md

@@ -4,6 +4,19 @@
 
 This is the Microsoft official Go MSSQL driver repository. This document provides comprehensive instructions for working effectively in this codebase, including build, test, lint, and validation processes.
 
+## Code Style
+- Minimal code, maximum modularity
+- Extract repeated logic into helpers
+- No verbose patterns
+- No redundant comments (e.g., `// TestX tests the X function` - the name says it)
+- Comments should add information, not repeat what the code already says
+
+## Testing
+- Use `github.com/stretchr/testify/assert` for assertions
+- Let exceptions be exceptions: use `t.Fatal(err)` not `t.Skipf` when tests should fail
+- Table-driven tests with `t.Run` for multiple cases
+- No redundant test scaffolding - extract helpers when patterns repeat 3+ times
+
 ## Working Effectively
 
 ### Bootstrap and Build the Repository
@@ -75,9 +88,23 @@ Always run these commands before committing changes:
 - `go test ./msdsn ./internal/... ./integratedauth ./azuread` - run unit tests (~1.5 seconds total)
 - If you have SQL Server available: `go test ./...` with 30+ minute timeout. NEVER CANCEL.
 
+### Code Coverage Requirements
+**IMPORTANT**: This project enforces a strict **80% minimum code coverage** requirement.
+- All PRs must maintain project coverage at or above 80%
+- New code in PRs must also have at least 80% coverage
+- PRs that drop coverage below 80% will fail the Codecov status check
+- Coverage is configured in `codecov.yml` at the repository root
+
+To check coverage locally:
+```bash
+go test -coverprofile=coverage.out ./...
+go tool cover -func=coverage.out | tail -1  # Shows total coverage
+```
+
 The CI pipeline (.github/workflows/pr-validation.yml) runs:
-1. `go test -v ./...` against SQL Server 2019 and 2022 in Docker
-2. AppVeyor runs Windows-specific tests including named pipes and shared memory
+1. `go test -coverprofile=coverage.out -v ./...` against SQL Server 2019 and 2022 in Docker
+2. Uploads coverage to Codecov for enforcement
+3. AppVeyor runs Windows-specific tests including named pipes and shared memory
 
 ## Commit Message Format
 

.github/workflows/pr-validation.yml

@@ -29,4 +29,14 @@ jobs:
         export HOST=.
         docker run -m 2GB -e ACCEPT_EULA=1 -d --name sqlserver -p:1433:1433 -e SA_PASSWORD=$SQLCMDPASSWORD mcr.microsoft.com/mssql/server:${{ matrix.sqlImage }}
         sleep 10
-        go test -v ./...
+        go test -coverprofile=coverage.out -covermode=atomic -v ./...
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v4
+      with:
+        files: coverage.out
+        flags: unittests
+        name: go-${{ matrix.go }}-sql-${{ matrix.sqlImage }}
+        fail_ci_if_error: false
+      env:
+        CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+

.github/workflows/release-please.yml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - main
+  workflow_dispatch:
 
 permissions:
   contents: write
@@ -13,4 +14,7 @@ jobs:
   release-please:
     runs-on: ubuntu-latest
     steps:
-      - uses: google-github-actions/release-please-action@v4
+      - uses: googleapis/release-please-action@v4
+        with:
+          config-file: release-please-config.json
+          manifest-file: .release-please-manifest.json

.gitignore

@@ -6,9 +6,20 @@
 *.log
 *.swp
 *~
+
+# Coverage artifacts
 coverage.json
 coverage.txt
 coverage.xml
+coverage.out
+*.out
+coverage/
+cov/
+cov*
+integ_cov*
+final.out
+coverage_all.txt
+
 testresults.xml
 .azureconnstr
 

CONTRIBUTING.md

@@ -43,4 +43,33 @@ This project uses [Release Please](https://github.com/googleapis/release-please)
 - ✅ `feat!: remove deprecated connection parameters`
 - ✅ `chore: update dependencies`
 - ❌ `Update README` (should be `docs: update README`)
-- ❌ `Bug fix` (should be `fix: <description>`)
+- ❌ `Bug fix` (should be `fix: <description>`)
+
+## Code Coverage Requirements
+
+This project enforces a **strict 80% minimum code coverage** requirement to maintain code quality and ensure inclusion in the [awesome-go](https://github.com/avelino/awesome-go) directory.
+
+### Requirements
+
+- **Project coverage**: Must stay at or above 80%
+- **Patch coverage**: New code in PRs must be at least 80% covered
+
+### Checking Coverage Locally
+
+```bash
+# Run tests with coverage
+go test -coverprofile=coverage.out ./...
+
+# View total coverage
+go tool cover -func=coverage.out | tail -1
+
+# Generate HTML coverage report
+go tool cover -html=coverage.out -o coverage.html
+```
+
+### Tips for Maintaining Coverage
+
+1. Write unit tests for new functions and methods
+2. Test error paths, not just happy paths
+3. Use table-driven tests for comprehensive coverage
+4. Check coverage before submitting PRs

README.md

@@ -2,7 +2,7 @@
 
 [![Go Reference](https://pkg.go.dev/badge/github.com/microsoft/go-mssqldb.svg)](https://pkg.go.dev/github.com/microsoft/go-mssqldb)
 [![Build status](https://ci.appveyor.com/api/projects/status/jrln8cs62wj9i0a2?svg=true)](https://ci.appveyor.com/project/microsoft/go-mssqldb)
-[![codecov](https://codecov.io/gh/microsoft/go-mssqldb/branch/master/graph/badge.svg)](https://codecov.io/gh/microsoft/go-mssqldb)
+[![codecov](https://codecov.io/gh/microsoft/go-mssqldb/branch/main/graph/badge.svg)](https://codecov.io/gh/microsoft/go-mssqldb)
 
 
 ## Install

accesstokenconnector_test.go

@@ -10,6 +10,8 @@ import (
 	"fmt"
 	"strings"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func TestNewAccessTokenConnector(t *testing.T) {
@@ -91,3 +93,27 @@ func TestAccessTokenConnectorFailsToConnectIfNoAccessToken(t *testing.T) {
 		t.Fatalf("expected error to contain %q, but got %q", errorText, err)
 	}
 }
+
+func TestNewAccessTokenConnector_TokenProviderCalled(t *testing.T) {
+	// Test that the token provider is actually called and returns expected value
+	dsn := "Server=server.database.windows.net;Database=db"
+	expectedToken := "test-token-123"
+	called := false
+	
+	tp := func() (string, error) {
+		called = true
+		return expectedToken, nil
+	}
+	
+	connector, err := NewAccessTokenConnector(dsn, tp)
+	assert.NoError(t, err, "NewAccessTokenConnector()")
+	
+	c, ok := connector.(*Connector)
+	assert.True(t, ok, "connector should be of type *Connector")
+	
+	// Call the security token provider
+	token, err := c.securityTokenProvider(context.Background())
+	assert.NoError(t, err, "securityTokenProvider()")
+	assert.True(t, called, "Token provider should be called")
+	assert.Equal(t, expectedToken, token, "token value")
+}