feat(merge): add support for merging from a list of source files

cmd/relspec/testhelpers_test.go

@@ -0,0 +1,180 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"testing"
+)
+
+// minimalColumn is used to build test JSON fixtures.
+type minimalColumn struct {
+	Name          string `json:"name"`
+	Table         string `json:"table"`
+	Schema        string `json:"schema"`
+	Type          string `json:"type"`
+	NotNull       bool   `json:"not_null"`
+	IsPrimaryKey  bool   `json:"is_primary_key"`
+	AutoIncrement bool   `json:"auto_increment"`
+}
+
+type minimalTable struct {
+	Name    string                   `json:"name"`
+	Schema  string                   `json:"schema"`
+	Columns map[string]minimalColumn `json:"columns"`
+}
+
+type minimalSchema struct {
+	Name   string         `json:"name"`
+	Tables []minimalTable `json:"tables"`
+}
+
+type minimalDatabase struct {
+	Name    string          `json:"name"`
+	Schemas []minimalSchema `json:"schemas"`
+}
+
+// writeTestJSON writes a minimal JSON database file with one schema ("public")
+// containing tables with the given names. Each table has a single "id" PK column.
+func writeTestJSON(t *testing.T, path string, tableNames []string) {
+	t.Helper()
+
+	tables := make([]minimalTable, len(tableNames))
+	for i, name := range tableNames {
+		tables[i] = minimalTable{
+			Name:   name,
+			Schema: "public",
+			Columns: map[string]minimalColumn{
+				"id": {
+					Name:          "id",
+					Table:         name,
+					Schema:        "public",
+					Type:          "bigint",
+					NotNull:       true,
+					IsPrimaryKey:  true,
+					AutoIncrement: true,
+				},
+			},
+		}
+	}
+
+	db := minimalDatabase{
+		Name:    "test_db",
+		Schemas: []minimalSchema{{Name: "public", Tables: tables}},
+	}
+
+	data, err := json.Marshal(db)
+	if err != nil {
+		t.Fatalf("failed to marshal test JSON: %v", err)
+	}
+	if err := os.WriteFile(path, data, 0644); err != nil {
+		t.Fatalf("failed to write test file %s: %v", path, err)
+	}
+}
+
+// convertState captures and restores all convert global vars.
+type convertState struct {
+	sourceType    string
+	sourcePath    string
+	sourceConn    string
+	fromList      []string
+	targetType    string
+	targetPath    string
+	packageName   string
+	schemaFilter  string
+	flattenSchema bool
+}
+
+func saveConvertState() convertState {
+	return convertState{
+		sourceType:    convertSourceType,
+		sourcePath:    convertSourcePath,
+		sourceConn:    convertSourceConn,
+		fromList:      convertFromList,
+		targetType:    convertTargetType,
+		targetPath:    convertTargetPath,
+		packageName:   convertPackageName,
+		schemaFilter:  convertSchemaFilter,
+		flattenSchema: convertFlattenSchema,
+	}
+}
+
+func restoreConvertState(s convertState) {
+	convertSourceType = s.sourceType
+	convertSourcePath = s.sourcePath
+	convertSourceConn = s.sourceConn
+	convertFromList = s.fromList
+	convertTargetType = s.targetType
+	convertTargetPath = s.targetPath
+	convertPackageName = s.packageName
+	convertSchemaFilter = s.schemaFilter
+	convertFlattenSchema = s.flattenSchema
+}
+
+// mergeState captures and restores all merge global vars.
+type mergeState struct {
+	targetType    string
+	targetPath    string
+	targetConn    string
+	sourceType    string
+	sourcePath    string
+	sourceConn    string
+	fromList      []string
+	outputType    string
+	outputPath    string
+	outputConn    string
+	skipDomains   bool
+	skipRelations bool
+	skipEnums     bool
+	skipViews     bool
+	skipSequences bool
+	skipTables    string
+	verbose       bool
+	reportPath    string
+	flattenSchema bool
+}
+
+func saveMergeState() mergeState {
+	return mergeState{
+		targetType:    mergeTargetType,
+		targetPath:    mergeTargetPath,
+		targetConn:    mergeTargetConn,
+		sourceType:    mergeSourceType,
+		sourcePath:    mergeSourcePath,
+		sourceConn:    mergeSourceConn,
+		fromList:      mergeFromList,
+		outputType:    mergeOutputType,
+		outputPath:    mergeOutputPath,
+		outputConn:    mergeOutputConn,
+		skipDomains:   mergeSkipDomains,
+		skipRelations: mergeSkipRelations,
+		skipEnums:     mergeSkipEnums,
+		skipViews:     mergeSkipViews,
+		skipSequences: mergeSkipSequences,
+		skipTables:    mergeSkipTables,
+		verbose:       mergeVerbose,
+		reportPath:    mergeReportPath,
+		flattenSchema: mergeFlattenSchema,
+	}
+}
+
+func restoreMergeState(s mergeState) {
+	mergeTargetType = s.targetType
+	mergeTargetPath = s.targetPath
+	mergeTargetConn = s.targetConn
+	mergeSourceType = s.sourceType
+	mergeSourcePath = s.sourcePath
+	mergeSourceConn = s.sourceConn
+	mergeFromList = s.fromList
+	mergeOutputType = s.outputType
+	mergeOutputPath = s.outputPath
+	mergeOutputConn = s.outputConn
+	mergeSkipDomains = s.skipDomains
+	mergeSkipRelations = s.skipRelations
+	mergeSkipEnums = s.skipEnums
+	mergeSkipViews = s.skipViews
+	mergeSkipSequences = s.skipSequences
+	mergeSkipTables = s.skipTables
+	mergeVerbose = s.verbose
+	mergeReportPath = s.reportPath
+	mergeFlattenSchema = s.flattenSchema
+}