test: expand coverage across readers, writers, cmd, ui, diff and merge

Implements tests/_plans and previously deferred packages; updates plan
README with new coverage numbers.

pkg/diff/schema_attrs_test.go

@@ -0,0 +1,63 @@
+package diff
+
+import (
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+func TestCompareSchemaDetails_DescriptionAndOwner(t *testing.T) {
+	mk := func(desc, owner string) *models.Schema {
+		s := models.InitSchema("public")
+		s.Description, s.Owner = desc, owner
+		return s
+	}
+	tests := []struct {
+		name       string
+		src, tgt   *models.Schema
+		wantFields []string
+	}{
+		{"identical", mk("d", "o"), mk("d", "o"), nil},
+		{"description", mk("a", "o"), mk("b", "o"), []string{"description"}},
+		{"owner", mk("d", "x"), mk("d", "y"), []string{"owner"}},
+		{"both", mk("a", "x"), mk("b", "y"), []string{"description", "owner"}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := compareSchemaDetails(tt.src, tt.tgt)
+			if len(tt.wantFields) == 0 {
+				if got != nil {
+					t.Fatalf("expected no change, got %+v", got)
+				}
+				return
+			}
+			if got == nil || len(got.Changes) != len(tt.wantFields) {
+				t.Fatalf("changes: %+v", got)
+			}
+			for _, f := range tt.wantFields {
+				c, ok := got.Changes[f].(map[string]any)
+				if !ok {
+					t.Fatalf("missing %s: %+v", f, got.Changes)
+				}
+				if c["source"] == c["target"] {
+					t.Errorf("%s source and target equal: %v", f, c)
+				}
+			}
+		})
+	}
+}
+
+func TestCompareDatabases_SchemaAttrsCounted(t *testing.T) {
+	src, tgt := models.InitDatabase("a"), models.InitDatabase("b")
+	s1, s2 := models.InitSchema("public"), models.InitSchema("public")
+	s1.Owner, s2.Owner = "alice", "bob"
+	src.Schemas, tgt.Schemas = append(src.Schemas, s1), append(tgt.Schemas, s2)
+
+	res := CompareDatabases(src, tgt)
+	if res.Schemas == nil || len(res.Schemas.Modified) != 1 {
+		t.Fatalf("schema owner change not reported: %+v", res.Schemas)
+	}
+	if ComputeSummary(res).Schemas.Modified != 1 {
+		t.Error("summary must count the modified schema")
+	}
+}